Question

Find the area of the polygon

Answer 1

The area A is given in terms of the side length s, apothem a, and number of sides n as

... A = n·s·a/2

For the given dimensions, your octagon has an area of

... A = 8·4·4.8/2 = 76.8 . . . . units²

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We cannot see the instructions for rounding, so we leave that to you.