First, lets work on the 3-pt shaded area (inside) of a high school court.
this is actually equal to a half circle
Area of circle = pie x radius^2
= 3.1416 x (19feet and 9 inches)^
= 3.1416 x (19.75 feet)^2
= 3.1416 x 390.0625 sq. ft
= 1225.4175 sq. ft.
since its a half circle then area inside 3 pt line = 1225.4175 / 2 =612.709 sq.ft.
now lets work on the NBA court which is definitely not a half circle.
Theres a right triangle formed by the
a. radius = 23 ft and 9 inches = 23.75 ft = hypotenuse
b. the line on the baseline = 50/2 - 3 = 25 -3 = 22 feet (base of triangle), and
c. the line parallel to the side line but length is unknown ---> height
lets solve for the length of the line parallel to the side line ( so we can solve for the area of this triangle)
since right triangle...... hyp^2 = base^2 + height^2
23.75^2 = 22^2 + height^2
564.0625 - 484 = height^2
80.0625 = ht^2
8.9478 = height
Now lets solve for area of triangle = 1/2(base)(height)
= 1/2(22)(8.9478) = 98.4254 sq.ft
since there'll be these imaginary traingles on both sides, we multiply the area of triangle by 2 = 98.4254 x 2 = 196.8508 sq.ft.
the only problem left is getting the area in the middle bound by the 2 triangles. to solve this we nid the angle (A) formed by the triangle at the point under the hoop.
cos A = adjacent side / hypotenuse
= 22 / 23. 75
= 22.1324 degrees
since there are 2 of these angles = 2 x 22.1324 degrees
= 44.2648 degrees
subtract it to the angle of a straight line => 180 - 44.2648 = 135.7352 degrees --------> means that the area inside this angle is --------->
135.7352 / 360 = 0.377 of the area of the circle that could have been formed given the radius of 23.75 feet
now lets solve for the area of that would be circle = pie x radius^2
A = 3.1416 x 23.75^2
= 3.1416 x 564.0625 sq.ft.
= 1772.05875 sq.ft.
actual area = 1772.05875 x 0.377 = 668.066
Add to this the combined area of the 2 triangles =
= 668.066 + 196.8508 = 864.9168 sq.ft.
Now we know the areas of both the NBA court and a college court, we can find the difference.
difference = 864.9168 - 612.709 = 252.2078 sq.ft.
Answer: 252.2078 sq.ft.