A 20 foot extension ladder leans against Paul’s barn wall creating a 65° angle with the ground. How many feet (to the nearest tenth) above the ground is the point where the ladder touches the wall?

The ladder forms a rectangle triangle with an Hypotenuse equals to 20 and an angle of 65 degrees adjacent to the hypotenuse, the height being a leg of the triangle, then:

sin 65 = H/20 => H=20 X sin65 = 18.13 feet