Area of the circle = π * (35 yd)^2
Let A be the area of the sector subtended by a central angle measuring 80º. Then
A / (π * (35 yd)^2) = 80º / 360º ==> A = 2450π/9 yd^2 ≈ 854.78 yd^2
Subtract from A the area of the triangle, whose base has length 45 yd and with height 25 yd:
A - 1/2 * (45 yd) * (25 yd) ≈ 292.28 yd^2
This is the area of the missing circular segment.
Then the area of the playground is equal to the area of the circle minus this area,
π * (35 yd)^2 - 292.28 yd^2 ≈ 3554 yd^2
