The length of a side of the base of a pyramid is 7 m, and the slant height is 10 m. Find the surface area of the pyramid. A) 329 m² B) 189 m² C) 140 m² D) 119 m² E) 238 m²

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Quizplus · Accepted Answer

The surface area of a pyramid is found by adding the base area to the lateral surface area. The base area is $7m \times 7m = 49m^2$. Each triangular face has a base of 7m and a slant height of 10m, so the area of one triangle is $\frac{1}{2} \times base \times slant\ height = \frac{1}{2} \times 7m \times 10m = 35m^2$. Since there are 4 triangles, their total area is $35m^2 \times 4 = 140m^2$. Adding the base area, the total surface area is $140m^2 + 49m^2 = 189m^2$.

The Length of a Side of the Base of a Pyramid