ISEE Upper Level Math : How to find an angle in a right triangle

Study concepts, example questions & explanations for ISEE Upper Level Math

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Example Questions

Example Question #1 : How To Find An Angle In A Right Triangle

Which of the following is true about a triangle with two angles that measure  and ?

Possible Answers:

This triangle is obtuse.

This triangle is scalene.

This is a right isosceles triangle.

This triangle is scalene and right.

This is an equilateral triangle.

Correct answer:

This is a right isosceles triangle.

Explanation:

The sum of the two given angles is 90 degrees, which means that the third angle should be a right angle (90 degrees). We also know that two of the angles are equal. Therefore, the triangle is right and isosceles.

Example Question #2 : How To Find An Angle In A Right Triangle

What is the value of x in a right triangle if the two acute angles are equal to 5x and 25x?

Possible Answers:

Correct answer:

Explanation:

In a right triangle, there is one right angle of 90 degrees, while the two acute angles add up to 90 degrees. 

Given that the two acute angles are equal to 5x and 25x, the value of x can be calculated with the equation below:

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