Answer:
Explanation:
We can use the Pythagorean theorem to solve this problem. Let's call the length of the ladder "L". The ladder, the wall of the house, and the ground form a right triangle. The distance between the ladder and the house is the base of the triangle, which is 15 feet. The height of the triangle is the distance from the ground to the spotlight, which is 20 feet. The length of the ladder is the hypotenuse of the triangle.
Using the Pythagorean theorem, we have:
L^2 = 15^2 + 20^2
L^2 = 225 + 400
L^2 = 625
L = sqrt(625)
L = 25
Therefore, a ladder of at least 25 feet is needed for the electrician to reach the place where the light is mounted.