Find the area of the ring-the shaded region

The area of the (ring) - the shaded region is 75.36 in²

Solution:

The value of π = 3.14

Radius of the inner circle = 5 in

Area of the inner circle = πr²

                                       = π × 5²

Area of the inner circle = 25π

Radius of the outer circle = (5 + 2) = 7 in

Area of the outer circle = πr²

                                       = π × 7²

Area of the outer circle = 49π

Area of the shaded ring = Area of the outer circle – Area of the inner circle

                                        = 49π – 25π

                                        = 24π

                                        = 24 × 3.14

                                        = 75.36 in²

The area of the (ring) - the shaded region is 75.36 in².                                

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: