Question

A 10 foot ladder must make an angle of 30 with the ground if it is to reach a certain window. what angle must a 20 foot ladder make with the ground to reach the same window?

a. 10.5 degree
b. 12.5 degree
c. 14.5 degree
d. 16.5 degree

Answer 1

c) 14.5 degree

Explanation:

Answer 2

see the attached figure to better understand the problem

we know that

in the triangle ABC
sin 30=AB/10------> AB=10*sin 30-----> AB=10*(1/2)----> 5 ft

in the triangle ABD
sin D=AB/20--------> sin D=5/20----> sin D=0.25
D=arc sin(0.25)-----> D=14.48°------> D=14.5°

the answer is the option
c. 14.5 degree