Question

Find the formula, in terms of K, for the area of a regular octagon with apothem K and side of 10. A =

Amistre64 started tohelp me but i couldn't find the apothem formula. He says it should be A=8(k*10/2)

Answer 1

Area is \( \frac12 pa = \frac12 \times 80\times k = 40k ,\)

NOTE: \(p\) = perimeter and \(a\) is the apothem

Answer 2

the octagon can be broken up into 8 identical triangles
apothem is just a fancy word for the altitude of the triangle
so find the area of one triangle and multiply by 8