Robert sketches two rectangular prisms, A and B. Prism A's side lengths are 5 centimeters, 6 centimeters and 7 centimeters. Prism B's side lengths were twice those of prism A's: 10 centimeters, 12 centimeters, and 14 centimeters. Robert says that surface area of prism B is twice the surface area of prism A. Is he correct? If he is not, how many times as great as prism A's surface area is prism B's surface area? Show your work.

Question

Starr

Mathematics

31 March, 03:05

Robert sketches two rectangular prisms, A and B. Prism A's side lengths are 5 centimeters, 6 centimeters and 7 centimeters. Prism B's side lengths were twice those of prism A's: 10 centimeters, 12 centimeters, and 14 centimeters. Robert says that surface area of prism B is twice the surface area of prism A. Is he correct? If he is not, how many times as great as prism A's surface area is prism B's surface area? Show your work.

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Answers (1)

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Maxim Burton · Answer 1

Fasle

LH=legnth times height

HW=height times width

LW=legnth times width

surface area=2 (LH+LW+WH)

A surface area is 2 (5*6+5*7+6*7) = 214

b surface area is double everybody si

2 (10*12+10*14+12*14) = 856

214 times 2=428

he is wrong

how many times as great?

856/214=4

answer is 4 times

net is second drawing