As shown in the figure: the area of the shadow part is 50 square centimeters, find the area of the ring in the figure

As shown in the figure: the area of the shadow part is 50 square centimeters, find the area of the ring in the figure

Let the radius of the big circle be r and the radius of the small circle be r, then: 2R × R △ 2-2r × R △ 2 = 50, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & r2-r2 = 50 (square centimeter); the area of the ring: π R2 - π R2, = π × (r2-r2), = 3.14 × 50, = 157 (square centimeter); answer: the area of the ring is 157 square centimeter