Hi, I would suggest drawing out the basketball court.
The basketball court is 50 feet by 90 feet.
Now draw a diagonal line from one corner to the other corner forming two triangles.
Since the basketball court is a rectangle, then both triangles should be equal or similar.
The formula to find the diagonal line( the hypotenuse of the triangle) is a2 + b2 = c2
where a and b are sides of the triangle and c is the diagonal line (hypotenuse)
a=50 b=90 c=?
a2 + b2 = c2
502 + 902 = c2
2500 + 8100 = c2
10600 = c2
103 = c2
Answer: 103 feet (rounded to the nearest foot)
I hope this helps.
Please feel free to reach out to me if you still need any clarification.