trigometry
posted by jake .
1. A 16foot ladder on ground level is leaning against a house. If the base of the ladder is placed 5.0 feet from the house, what is the angle formed at the top of the ladder?
A. 24°
B. 18°
C. 72°
D. 20°
please help I don't know how to do this

It is always good to draw a picture. You have a right triangle with hypotenuse of 16. The side opposite the angle that you are looking for is 5.
If you take the opp/hypotenuse = sine of the angle
5/16 = sin of angle.
You can use your calculator to find the value of the angle. This is the angle whose sine is 5/16 or .3125.
If you have trouble figuring that out. you can take the sin of each of the angles given and see if that value equals .3125 which is 5/16. 
20.5