Right Triangles and Trigonometry: Ratios of Right Triangles

Parts of a Right Triangle

Although we discussed the various parts in a right triangle in the last section, it is worth a quick review before we move on to the topics in this section.

Triangle ABC with sides a, b, and c
Right Triangle ABC

 

The hypotenuse is side c, which is opposite the right angle.

Side a is opposite angle A and side b is adjacent to angle A.
Side b is opposite angle B and side a is adjacent to angle B.

It is important that you can tell which side is adjacent to an angle and which side is opposite an angle.

Triangle XYZ with sides 5, 12, and 13
Right Triangle XYZ

 

Think and Click Think & Click: Parts of a Right Triangle

Use the triangle above to answer the following questions.

1. What is the length of the hypotenuse?

13

2. What is the length of the side opposite angle X?

5

3. What is the length of the side adjacent to angle X?

12

4. What is the length of the side opposite angle Y?

12

5. What is the length of the side adjacent to angle Y?

5