Texas Instruments TI-30X Teachers Guide - Page 15

Trig Functions (Continued) Activity Present the following problem to students: You need to build a ramp to your front door. The distance from the ground to the bottom of the door is 1.5 feet. You don’t want the angle of incline to be more than 6 degrees. The distance from the street to the door is 20 feet. Is there enough room to build the ramp? Procedure 1. Make a drawing of the problem. 1.5 ft. A 20 ft. 2. Use the trigonometric ratio tan = opposite leg ¾ adjacent leg to find angle A. Angle A is 4.3 degrees (rounded to the nearest tenth). Yes, there is enough room to build the ramp. Extension Present the following problem to students: You want to start the ramp 15 feet away from the door. Can you do that and still have the angle of incline be less than 6 degrees? Yes, angle A is 5.7º. ³ 1. Press % \. tan-1( 2. Enter 1.5 W 20 and press E