One of the properties of similar triangles is that ratios of side lengths are the same.

The ratios that compare side lengths of right triangles are given special names, and

are generally known as trigonometric ratios. They depend on the perspective of one

of the acute angles. Side lengths are named opposite, adjacent, and the hypotenuse.

sine ratio: cosine ratio: tangent ratio:

Example: Determine each ratio.

A

B

Csin A = sin B =

cos A = cos B =

tan A = tan B =

Part 2: Determine the measure of angles A and B in the triangle above.

4

3

C

4

3

Trigonometric Ratios

Calculate the unknown angles to the nearest degree.

4 cm

15 mm 9 cm

12 mm