Question 1190453
the ladder and the wall and the ground form a right triangle.
the opposite side from the angle of inclination is equal to the height which is equal to 15 feet.
the length of the ladder is the hypotenuse of the right triangle which is equal to 20.
let x = the angle.
you get:
sin(x) = 15/20
x = arcsin(15/20) = 48.59037789 degrees.


let me know if you have any questions.
theo