How is this one done?

Complete the steps, which describe how to find the area of the shaded portion of the circle. find the area of the sector by multiplying the area of the circle by the ratio of the to 360. subtract the area of the triangle from the area of the sector.

Collin did the work to see if 10 is a solution to the equation r/4=2.4

Find the center of the circle that can be circumscribed about efg with e(4,4) f(4,2) g(8,2)