OXYZ is a tetrahedron whose faces are identical equilateral triangles of side 10 m each. Given that the slant height of pyramid is 5 square root 3 metres

find its total surface area leaving your answer correct to 3 significant figures.

1 answer

All that we really needed to know was that the sides were 10 m each for each of the 4 triangles.
We could have found the height using Pythagoras.

Area of one of them = (1/2)base x height = (1/2)(10)(5√3)
So four of them will have an area of
4(1/2)(10)(5√3) m^2 = 100√3 m^2 or appr .....