Question

Find the surface area of the regular triangular pyramid.

Answer 1

The surface of the pyramid: base + surface area of the sides.

The base area is:

By Heron formula,
s=8+8+8/2
=12

_/12(12-8)(12-8)(12-8)
=_/12(4)(4)(4)
=_/768
=27.7128..
≈27.71sq.units

The side surface areas:
(18×8/2)×3
=144/2×3
=216 sq.units

The total surface area:
216+27.71
=243.71 sq.units

Thus, 243.71 sq.units is the answer.

Hope it helps!