Texas Instruments TI-34 II Explorer Plus User Manual page 17

Trig Functions
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.
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.
© 1999 T I
EXAS NSTRUMENTS
(Continued)
20 ft.
I
NCORPORATED
A
³ 1. Press % ‚
2. Press % B " " " "
3. Enter 1.5 W 20 and press
³ 1. Enter 1.5 ¾ ¾ 15 and press
2. Press % B ! <
TI-34 Û: A Guide for Teachers
.
1
" <.
tan -1 (
E <.
tan (1.5¾ ¾ 20)
-1
4.3
<.
0.1
% i E <.
tan (Ans)
-1
5.7
11