A pyramid composed of four equilateral triangles, called a tetrahedron, has a one-side length of 5 meters. What is its surface area? Round the answer to the nearest tenth.

The area of an equilateral triangle is (1/2) bh. The base is 5, so using the Pythagorean theorem we get h by:

5² = (5/2) ² + h²

h = √18.75

h = 4.33

So the area of one face is (1/2) (5) (4.33) = 10.825m²

The total area is 4 (10.825m²) = 43.3m²