Question

To find the surface area of the pyramid, in square inches, Vikram wrote (33.2) (34.2) + 4 (one-half (34.2) (28.4)). What error did Vikram make? He used the same expression for the area of all four lateral faces. He used the wrong expression to represent the area of the base of the pyramid. He used the wrong value as the height when he found the area of the lateral faces. He used an expression for surface area that only finds the total area of three faces.

Answer 1

B. He used the wrong expression to represent the area of the base of the pyramid.

Explanation:

Given

See attachment for pyramid

`Area = (33.2)(34.2) + 4 * (1)/(2) * 34.4 * 28.4`

Required

Vikram's error

The surface area of a square pyramid is:

`Area = Base\ Area + 4 * Area \triangle`

Where

`Base\ Area = Length * Length`

`Base\ Area = 34.2 * 34.2`

`4 * Area \triangle = 4 * (1)/(2) * Base * Height`

`4 * Area \triangle = 4 * (1)/(2) * 34.2 * 28.4`

So:

`Area = Base\ Area + 4 * Area \triangle`

`Area = 34.2 * 34.2 + 4 * (1)/(2) * 34.2 * 28.4`

By comparing the calculated expression with

`Area = (33.2)(34.2) + 4 * (1)/(2) * 34.4 * 28.4`

Option (b) is correct