Answer:
17 feet
Step-by-step explanation:
A right angle has 3 sides: the adjacent, the opposite and the hypotenuse.
The hypotenuse is the largest side of the right angle
The shorter sides are 15 feet and 8 feet which should represent opposite and adjacent sides respectively
Opposite = 15 feet
Adjacent = 8 feet
Hypotenuse = x feet
Using Pythagoras theorem to solve
Hypotenuse ² = opposite ² + adjacent ²
x² = 15² + 8²
x² = 225 + 64
x² = 289
Find the square root of both sides
√x² = √289
x = 17 feet
The 3rd side is 17 feet
