Question

Which shows the dimensions of two rectangular prisms that have volumes of 72 cm3 but different surface areas? A. 6 cm by 3 cm by 4 cm; 12 cm by 2 cm by 3 cm B. 2 cm by 4 cm by 9 cm; 9 cm by 4 cm by 2 cm C. 3 cm by 3 cm by 8 cm; 2 cm by 6 cm by 8 cm D. 6 cm by 3 cm by 4 cm; 9 cm by 4 cm by 3 cm

Answer 1

A

Explanation:

A, is the answer

Answer 2

To solve, lets find the volumes of all of the options...

V=l*w*h

A.
6*3*4=72cm³
12*2*3=72cm³

B.
2*4*9=72cm³
9*4*2=72cm³

C.
3*3*8=72cm³
2*6*8=96cm³

D.
6*3*4=72cm³
9*4*3=108cm³

We can conclude that C & D aren't the answer, since they contain prisms that don't have a volume of 72cm³.

Now lets solve for the surface area of A and B...

A.
sA=2(wh+lw+lh)=2(6*3+4*6+4*3)=2(18+24+12)=2(54)=108cm²
sA=2(wh+lw+lh)=2(12*2+3*12+3*2)=2(24+36+6)=2(56)=112cm²


B.
sA=2(wh+lw+lh)=2(2*4+9*2+9*4)=2(8+18+36)=2(62)=124cm²
sA=2(wh+lw+lh)=2(9*4+2*9+2*4)=2(36+18+8)=2(62)=124cm²

A is the only option with both similar volumes of 72cm³ and different surface areas...

Answer=A