A plane, parallel to the center of the sphere, passes through the sphere at a distance of 20 cm from the center. The radius of the circular cross section is 15cm What is the radius of the sphere?

28

step-by-step explanation:

8+8+6+6

correct

step-by-step explanation:

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: