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The base of the roof of a building has a pentagonal shape

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by VJesus12 » Mon Mar 19, 2018 3:55 am
The base of the roof of a building has a pentagonal shape. The roof is constructed as a regular pyramid with a pentagon as its base. What is the total area of the lateral segments of the roof?

(1) The base of the pyramid has a perimeter of 30 meters.

(2) The faces of the pyramid are equal triangles.

The OA is E.

I don't understand this question. May any expert give me some help? It would be great if you clarify this DS question.
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Source: — Data Sufficiency |

by Jay@ManhattanReview » Mon Mar 19, 2018 10:04 pm
VJesus12 wrote:The base of the roof of a building has a pentagonal shape. The roof is constructed as a regular pyramid with a pentagon as its base. What is the total area of the lateral segments of the roof?

(1) The base of the pyramid has a perimeter of 30 meters.

(2) The faces of the pyramid are equal triangles.

The OA is E.

I don't understand this question. May any expert give me some help? It would be great if you clarify this DS question.
The phrase, "The roof is constructed as a regular pyramid with a pentagon as its base" means that the lateral faces of the pyramid are isosceles triangles; there are five such traingles; the vertices of them meet at point.

To get the area of the lateral segments of the roof, either we know the length of the base and the height of the pyramid OR the length of the base and the side of the triangular faces.

Let's take each statement one by one.

(1) The base of the pyramid has a perimeter of 30 meters.

=> Perimeter = 5*Base
3 = 5*Base
=> Base = 5 meters

Insufficient as we do not know the other parameter to get the area. Insufficient.

(2) The faces of the pyramid are equal triangles.

We already know this information. This is not an additional information.

Even combining the two statements will not help.

The correct answer: E

Hope this helps!

-Jay
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