question presents a circle in a circle (two circle sharing a common center). The inner circle radius = x inches. outer circle width = 6 inches. Find the expression that represents the area of the walkway in square inches.
- (area of inner circle + area of outer circle) - (area of inner circle) = area of outer circle
- (the area of the inner circle + area of outer circle) = (pi)(x+6)^2
- (the area of inner circle) = (pi)(x^2)
- Book solution states that the (area of inner + outer) = (pi)(x+6)^2 = pi(x^2 + 12x +36) ???
- pi(x^2 + 12x +36) - (pi)(x^2) = pi(12x +36) = (12pi)(x+3) ???
