Question

Every dimension of a triangular pyramid is multiplied by 10 to produce a new figure that is geometrically similar. What effect does this have on
the surface area of the pyramid?
OA. The surface area of the pyramid is multiplied by 10.
OB. The surface area of the pyramid is multiplied by 50.
OC. The surface area of the pyramid is multiplied by 100.
OD The surface area of the pyramid is multiplied by 1,000.
O E. The effect on the surface area cannot be determined.

Answer 1

Answer: Choice C

The surface area of the pyramid is multiplied by 100.

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Explanation:

Consider a square that is 3 by 3. Its area is 3*3 = 9.

Then we'll multiply each dimension by 10 to get a 30 by 30 square. The new larger area is 30*30 = 900. The jump from the old area (9) to the new area (900) is "times 100". We can write 100 as 10^2, where the base of that exponential is the scale factor 10.

This idea can apply to any surface area and not just squares. This is why the surface area of the enlarged pyramid is 100 times that of the original pyramid.

new surface area = 100*(old surface area)