Problem 1 :. Two angles are complementary. If one of the angles is double the other angle, find the two angles. Solution :. Let x be one of the angles. Then the other angle is 2x. Because x and 2x are complementary angles, we have. Divide each side by 3. If one angle is two times the sum of other angle and 3, find the two angles. Let x and y be the two angles which are complementary. Given : One angle is two times the sum of other angle and 3. Subtract 6 from each side. What is the measure of the complementary angle?

Let x be the measure of a complementary angle required. Two angles are supplementary. Let x and y be the two angles which are supplementary. From the information, "one angle is Now, Substitute 72 for y in 2. An angle and its one-half are complementary. Find the angle. Given : An angle and its one-half are complementary. If 5 times of one angle is 10 times of the other angle. Find the two angles. The measure of the supplement of angle A is 40 degrees larger than twice the measure of the complement of angle of A.

What is the sum in degrees, of the measures of the supplement and complement of angle A? Let x be the measure of angle A. Subtract from each side. The sum of supplement and complement of angle A is. Twice the complement of an angle is 24 degrees less than its supplement. What is the measure of the angle? Let x be the measure of angle.In this section, I teach students the basic thought process and mechanics for solving right triangles using trigonometry.

This is a teaching worksheet that requires students to do some reading and comprehension. We read through the packet together. I regulate the pace of the reading so that students are not speeding through without understanding what they are reading. I also rephrase, reiterate what is being said in the text just to reinforce it so that students are understanding.

When the handout calls for students to fill in blanks or solve problems, I first ask the students to work independently. Then I have them compare their responses with their A-B partners.

Finally, I reveal the answer or demonstrate the solution process. After the first page of the handout, I want to make sure that students understand when they can and cannot use Pythagorean Theorem and when they can and cannot use Trigonometric ratios to solve for the missing side length in a right triangle. On page 2, I introduce a decision-making framework that helps students to understand problems and map out a solution path. Students get to solve problems two ways on their own on page 3.

On page 4, I discuss inverse functions. At this point the text gets dense so I usually stop to write on the whiteboard to make sure students are getting the ideas being presented. At the end of this page, students should understand that sine, cosine and tangent are functions that take angle measures and output ratios. They should also know that the inverse trig functions take ratios and output angle measures.

They should also know how to use inverse trig functions to find unknown angle measures in right triangles.

At this point, I turn to the textbook to find application problems that involve angle of elevation and depression. I find that it is important to model a good number of these problems for students so that they can see the thought process that goes into solving these problems.

I spend minutes modeling problems. I repeatedly use the decision-making framework. Asking myself aloud "Ok Which side do I have? Which do I desire? Which ratio should I use? Is my variable in the numerator or in the denominator? For me, teaching students to organize their brains for decision making is one of my broader goals in the geometry course and this is a good opportunity to make progress on that goal.

One thing I stress in my demonstrations is postponing calculations until the very end. Instead it would be better to say x equals 15sin34and is approximately equal to 8. I give students numerous problems to start in class and finish for homework.

During my demonstration, I tell students that they have two options: They can pay attention to my modeling or if they are ready to work independently they can do so quietly without communicating with anyone else. That way students who want to pay attention to the demonstrations can do so without distractions and those who feel confident can get the practice they need.

Some students like a challenge. Not only that, a broader goal in the class is to get students used to the idea that some problems don't have numerical answers. These problems force us to deal with structures and relationships as opposed to focusing on computations. I give students a day or two to work on this at home and I demonstrate the solution once students have all had their go at it.

Empty Layer. Home Professional Learning. Professional Learning. Learn more about.SAT Math. That being said, you still want to get those questions right, so you should be prepared to know every kind of triangle: right triangles, isosceles triangles, isosceles right triangles—the SAT could test you on any one of them.

This article should be all you need to prepare you to tackle SAT triangle questions. A triangle is a flat figure made up of three straight lines that connect together at three angles. As we look at the many different types, you'll notice that many categories of triangles will be subsets of other categories of triangles and the definitions will continue to narrow.

### Geometry Problems and Questions with Answers for Grade 9

An equilateral triangle is a triangle that has three equal legs and three equal angles. If you are familiar with your circlesthen you know that any and all radii of a circle are equal. And we know that having three equal legs of a triangle means we have an equilateral triangle. We also know that equilateral triangles have three equal inner angles, all of which are 60 degrees. This means that angle ABO is 60 degrees. The sides opposite equal angles will always be equal, and the angles opposite equal sides will always be equal.

This knowledge will often lead you to the correct answers for many SAT questions in which it seems you are given very little information. The answer is Understanding these types of triangles and their formulas will save you a significant amount of time on triangle questions. An isosceles right triangle is just what it sounds like—a right triangle in which two sides and two angles are equal.

A triangle is a special right triangle defined by its angles. It's also half of an equilateral triangle.

Any consistent multiples of these numbers will also work the same way. So a right triangle could have leg lengths of:. Recognize this handsome fellow?

Because Pythagoras is here to impart his triangle wisdom. This is the box of formulas you will be given on every SAT math section. It will also save you time and effort to memorize these rather than flipping back and forth between the problem and the formula box. So memorize your formulas if possible and read below to see what these formulas mean and how to use them. Some formulas apply to all triangles while other formulas only apply to special triangles.

So let's first look at the triangle formulas that apply to any and all types of triangles. In a non-right triangle, you must create a new line for your height. There are also formulas that apply to right triangles and to specific types of right triangles. Let's take a look. The Pythagorean theorem allows you to find the side lengths of a right triangle by using the lengths of its other sides. Remember, if one side of a right triangle is 8 and its hypoteneuse is 10, then you automatically know the third side is 6.

Check out our trigonometry guide to learn all the formulas you need to know and to learn how to apply the formulas to SAT math questions. We know the second leg must also equal 6 because the two legs are equal in an isosceles triangle.

And we can also find the hypotenuse using the Pythagorean theorem because it is a right triangle. Check out our guide to SAT advanced integers and its section on roots if this process is unfamiliar to you. Just like with an isosceles right triangle, a triangle has side lengths that are dictated by a set of rules.

This knowledge can help you find the lengths of sides when given a more complex triangle problem. Dog is proud of your studiousness right now. So much studious.This is part of our collection of Short Problems.

Printable worksheets containing selections of these problems are available here:. Weekly Problem 45 - The diagram shows a regular pentagon with two of its diagonals.

If all the diagonals are drawn in, into how many areas will the pentagon be divided? Weekly Problem 28 - The diagram on the right shows an equilateral triangle, a square and a regular pentagon. What is the sum of the interior angles of the resulting polygon? Weekly Problem 40 - Given three sides of a quadrilateral, what is the longest that the fourth side can be? Weekly Problem 18 - Draw an equilateral triangle onto one side of a square.

Can you work out one particular angle? Weekly Problem 26 - The diagram shows two equilateral triangles. What is the value of x? Weekly Problem 10 - If you know how long Meg's shadow is, can you work out how long the shadow is when she stands on her brother's shoulders?

The diagram shows an equilateral triangle touching two straight lines. What is the sum of the four marked angles?

A square, regular pentagon and equilateral triangle share a vertex. What is the size of the other angle? Weekly Problem 1 - The diagram shows two circles enclosed in a rectangle.

What is the distance between the centres of the circles? How many rhombuses are there made up of two adjacent small triangles? Weekly Problem 26 - How many right angled triangles are formed by the points in this diagram? What is the size of angle VWY? Weekly Problem 28 - Two lines meet at a point. Another line through this point is reflected in both of these lines. What is the angle between the image lines?Using only elementary geometrydetermine angle x.

Provide a step-by-step proof. You may use only elementary geometry, such as the fact that the angles of a triangle add up to degrees and the basic congruent triangle rules side-angle-side, etc.

You may not use trigonomery, such as sines and cosines, the law of sines, the law of cosines, etc. This is the hardest problem I have ever seen that is, in a sense, easy. It really can be done using only elementary geometry.

This is not a trick question. Here is a very small hint. Here is a small hint. These hints are not spoilers. There is a review of everything you need to know about elementary geometry below. Remember to provide a step-by-step proof. There are tips for writing proofs below. Using only elementary geometry, determine angle x. This is a variation of the problem above. This is also a very hard problem that is, in a sense, easy. Sorry, but I'm not giving the answer nor the proof here.

You will just have to work on it until you either solve it or are driven insane. If you email me at k. If you think you have solved it, you can ask me if your answer is correct, but please also tell me how you got the answer.

The proof may be written informally, but you need to tell me all the steps, or at least the key steps, in your solution. It is helpful if you also send me a diagram. Try to persuade me that you are not just guessing. I have additional small, medium, and large hints, but you must first show your efforts to convince me that you have struggled valiantly.

Please don't search the the web for the answer — that's cheating. You will only deprive yourself of many hours of delicious frustration. Of the proofs posted on other websites, some are valid proofs and some are not. I did not invent these problems. After I first read problem 1, I worked on it for many hours over several days before I eventually figured it out. A couple of years later I came back to the problem, but I had forgotten my proof.

It took me many hours to figure it out again!

Problem 2 also took me many hours to solve. How hard are these problems? Any teenage student can understand the proof, but very very few are able to discover the proof on their own.Grade 9 geometry problems and questions with answers are presented.

These problems deal with finding the areas and perimeters of triangles, rectangles, parallelograms, squares and other shapes. Several problems on finding angles are also included.

Some of these problems are challenging and need a good understanding of the problem before attempting to find a solution. Also Solutions and detailed explanations are included. Free Mathematics Tutorials. About the author Download E-mail. Geometry Problems and Questions with Answers for Grade 9 Grade 9 geometry problems and questions with answers are presented. Angles A and B are complementary and the measure of angle A is twice the measure of angle B. The length of side AB is 20 cm.

E is a point between A and B such that the length of AE is 3 cm. F is a point between points D and C.

### Using Trigonometry to Solve Right Triangles

Find the length of DF such that the segment EF divide the parallelogram in two regions with equal areas. Find the measure of angle A in the figure below. ABC is a right triangle. AM is perpendicular to BC. The size of angle ABC is equal to 55 degrees.

Find the size of angle MAC. Find the size of angle MBD in the figure below. Find the size of angle DOB.

**Triangle angle challenge problem 2 (Hindi)**

Find the size of angle x in the figure. The rectangle below is made up of 12 congruent same size squares. Find the perimeter of the rectangle if the area of the rectangle is equal to square cm. Find the measure of angle QPB. Find the area of the given shape.

## Finding missing angles

Find the area of the shaded region. The vertices of the inscribed inside square bisect the sides of the second outside square. Find the ratio of the area of the outside square to the area of the inscribed square.

Solutions and detailed explanations are included.

Privacy Policy. Search website.Richard's Trigonometry Challenge. On this page I present some simple yet challenging Trigonometry problems. Its not calculus, nor is it rocket science, just simple right-angle trig. But, if you are reading this, you probably already have a computer!

Gain world-wide recognition! Solve the problem! I'll post the names of the first few people who correctly answer each question. If enough people want to know, I'll even post the solutions. E-mail the answer to me. Be sure and include an explanation of how you arrived at the answer, i.

I will not accept an answer without an explanation. I inflict pain and suffering on my students with stuff like this.

Think you know enough math to be a machinist? Click here for problem 1. Click here for problem 2. Click here for problem 3. Okay, okay, I know what your thinking. Click here for problem 5. Click here for problem 9 Try to solve this without iteration. No one has complained about this one being too easy! The beatings will continue until morale improves! Click here for problem 4 Click here for problem 5 Click here for problem 6 Click here for problem 7 Click here for problem 8 Click here for problem 9 Try to solve this without iteration.

Click here for problem 10 The beatings will continue until morale improves!

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