Among the following, an incorrect statement is a) the volume of the hollow sphere =4/3π (r^3—r^3), where r is the radius of the outer sphere and r is the radius of the inner sphere. b) the volume of the hemisphere of radius(r) is 2πr^3 c) the surface area sphere = 4πr^2 d) the surface area of a spherical shell = 4π (r^2—r^2), where r = external radius and r= internal radius please can someone say which one is incorrect

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.