9(7 + 8) = (9 x 7) + (9 x 8) = 63 + 72 = 135
As it is shown in the figure, the length of the square's side s is also the length of the circle's diameter d:
s = d = 28 in.
• Computing the area of the square:
A₁ = s²
A₁ = 28²
A₁ = 28 × 28
A₁ = 784 in² ✔
• Computing the area of the circle:
A₂ = π × r²
A₂ = π × (d/2)²
A₂ = π × (28/2)²
A₂ = π × 14²
A₂ ≈ 3.14 × 14 × 14
A₂ ≈ 615.44 in² ✔
—————
• The area of the shaded portion is equal to the difference between the area of the square and the area of circle:
A = A₁ – A₂
A ≈ 784 – 615.44
A ≈ 168.56 in² <——— this is the answer (1st option).
I hope this helps. =)
