INVERSE TRIG FUNCTIONS “TRIANGLE MEASURES” Section 8.3 Objective: To use trig ratios to find angle measures of right triangles and to solve real-world problems.

WHAT’S MY ANGLE?  5 10 S oh C ah T oa We want to “undo” the process to find the angle measure, so we use the inverse functions:  : Theta

WHAT’S MY ANGLE?  13 8 S oh C ah T oa

San Francisco, California, is famous for its steep streets. The steepness of a road is often expressed as a percent grade. Filbert Street, the steepest street in San Francisco, has a 31.5% grade. This means the road rises 31.5 ft over a horizontal distance of 100 ft. What is the angle the street makes with a horizontal line? 100 ft 31.5 ft 

Words to know… Angle of Elevation: Angle formed with a horizontal line when looking up. Angle of Depression: Angle formed with a horizontal line when looking down.   Note: The angle of elevation and angle of depression will have the same measure. 

Henry needs to build a wheel chair ramp for his home. He knows that the slope of the ramp must be between 1:12 and 1:20 to meet code. What measures can the angle of elevation be and still meet code? 1 12  20 The ramp can have an angle of elevation between 2.9  and 4.8  and still meet code.

Assignment WS: Inverse Trig Functions 1-14