Question

Find the lateral and total surface area of a regular triangle right pyramid with base $4$cm and slant height $7$cm. Take $\sqrt{3}\approx 1.73$.

Answer 1

Given $a=4$cm, $l=7$cm. We have to find L.S.A and T.S.A.
L.S.A. $=\frac{1}{2}Pl=\frac{1}{2}\times 3a\times l=\frac{1}{2}\times 3\times 4\times 7=42c{m}^2$.
Hence T.S.A. $=48.92c{m}^2$ approximately.