Question

find the area .
A regular octagon with radius 20 inches .

Answer 1

It's approximately 1931.37 square inches.

Answer 2

How ?

Answer 3

I'll be honest, I googled it. But the formula is here A=2(1+2)a2

Answer 4

Thats what i usually do .
the formula is area = apothem * perimeter.. or 1/2 * bc(sin A)
Which basically means bc is the side numbers times sin( angle degree) divided by 2

Answer 5

I'd just guess to plug in the data. I'm not exactly sure what an apothem is, unfortunately

Answer 6

@satellite73

Answer 7

Oh its algebra 2

Answer 8

Ah, here we go, an apothem is just the radius of the in-circle of a polygon. Which can be found using the length of a regular polygon and this equation

Answer 9

\[apothem = s/(2\tan(180/n))\]
S is the length of any of the sides, while N is the number of sides

Answer 10

i dont even know the length of the side, i have my notes from class with me they just dont help .

Answer 11

so that should be 20/2tan(180/8)

Answer 12

ah oh crab, the radius is 20, not the side, my bad

Answer 13

well there's a neato octagon calculator here, but I can't really take the time to teach myself this lil branch of algebra at the moment, I'm really sorry lass
http://rechneronline.de/pi/octagon.php