Question

Linda joined cardboard pieces to make a square pyramid, as shown below.



If the dimensions of the pyramid are doubled, which statement is true about the surface area of the new pyramid?

It will be four times the original pyramid’s surface area.

It will be one-fourth of the original pyramid’s surface area.

It will be two times the original pyramid’s surface area.

It will be half of the original pyramid’s surface area.

Answer 1

do the calculations

Original doubled


Base = 4x4 = 16 8 x 8 = 64

triangle 1/2 x 4 x 6 = 12 1/2 x 8 x 12 = 48

its very easy if you do some calculations.

Answer 2

2x

Answer 3

It will be four times the original pyramid’s surface area.
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The two pyramids are similar with a scale factor of 1 to 2.
If two solids are similar, then the square of their scale factor is equal to the ratio of their areas.
(1/2)^2 = 1/4.
The surface area of the new pyramid is 4 times that of the original.

Answer 4

thanks!