find the perimeter of a regular octagon with an area of 80 m and an apothem of 5m

1 answer

Look at one of the 8 congruent triangles.
The height of one of those is 5 m and let the base be b
each triangle has an area of 80/8 = 10 m^2

(1/2)(b)(5) = 10
5b = 20
b = 4
so we 8 sides of 4 m, for a perimeter of 32 m