To determine the length of the ladder needed for the electrician to reach the spotlight mounted 24 feet above the ground, with the base of the ladder positioned 18 feet away from the house, we can use the Pythagorean theorem.
The Pythagorean theorem states that in a right triangle, the square of the length of the hypotenuse \(c\) (the ladder, in this case) is equal to the sum of the squares of the lengths of the other two sides \(a\) and \(b\):
\[ c^2 = a^2 + b^2 \]
Here:
- \(a\) is the height from the ground to the spotlight (24 feet),
- \(b\) is the distance from the base of the ladder to the house (18 feet),
- \(c\) is the length of the ladder.
Now you can plug in the numbers:
\[ c^2 = 24^2 + 18^2 \] \[ c^2 = 576 + 324 \] \[ c^2 = 900 \] \[ c = \sqrt{900} \] \[ c = 30 \]
Therefore, the length of the ladder needed is \(30\) feet.