Question

A regular octagon has sides measuring about 4cm. If the octagon is divided into 8 congruent triangles, each has a height of 5 cm. What is the area of the octagon?

Answer 1

The area of a triangle is 1/2*base*height

So, do that for one of the triangles, since they're all the same 1/2*4*5=10cm squared

Multiply by 8 to find the total

10*8=80

80 cm squared.

Answer 2

Base of each triangle = about 4 cm
Height of each triangle = 5 cm

Area of each triangle = (1/2) (base) (height)
and there are 8 of them.

Total area = (8) x (1/2) x (base) x (height) =

                       (4) x (about 4 cm) x (5 cm) = about 80 cm² .