Geometry 8-2 Trigonometric Ratios A trigonometric (trig) ratio is a ratio of two sides of a right triangle. Use trig ratios when the right triangle only has one side length given and it is not a special right triangle (30-60 or 45-45)

1 st Trigonometric Ratio  The sine (sin):

2 nd Trigonometric Ratio  The cosine (cos):

3 rd Trigonometric Ratio  The tangent (tan): D EF

Recall the 30°-60°-90° Special Right Triangle Find the sin of the 60° angle. 30° 60°

Recall the 45°-45°-90° Special Right Triangle Find the tan of the 45° angle. 45° x x

Word Problem  You and your friends decide to build a bike ramp using a 4 ft piece of wood. You make a 20° angle with the ground. How high above the ground will the back wheel be when your bike goes off the ramp? 20° 4 x

 Find the length of side BC. Another Example 10.2 ft 15° C B A

Example Find the length of RT. 12° T S R 350 m