Given:
The perimeter of a backyard basketball court with four sides is 90 feet.
Two sides of the court are each 20 feet long.
One side of the court is 25 feet long.
To find:
The missing side length of the basketball court.
Solution:
Let x be the missing side length.
The three given sides of the basketball court are 20 feet, 20 feet, 25 feet.
We know that the perimeter is the sum of all sides.
The perimeter of a backyard basketball court with four sides is 90 feet.
Therefore, the missing side length is 25 feet and the correct option is B.