Answer:
692.82 m^2
Step-by-step explanation:
Regular tetrahedrons have four equivalent equilateral triangular faces, so only the side length of one is needed.
In practice, you could find the area of one triangular side and multiply it by 4. This is probably what your teacher wants you to do, but there is another way if you have a calculator...
To make it easier, use the following equation to calculate the surface area of a tetrahedron:
Surface Area = sqrt(3) * a^2 ( "a" represents edge length )
sqrt (3) * 20^2
sqrt (3) * 400
692.82032302 m^2
