Question

Find the surface area of the regular pyramid.

Answer 1

The surface area of the triangular pyramid = area of base + lateral surface area.

The surface area of the triangular pyramid $=\left(\frac{1}{2}\times 9\times 7.8+3\times \frac{1}{2}\times 9\times 10\right)$

$$\begin{gathered} =(35.1+135)y{d}^2 \\ =170.1y{d}^2 \end{gathered}$$

Final answer: The surface area of the triangular pyramid is $170.1y{d}^2$