Question

Find the area of a regular nonagon with an apothem 16.5 inches long and a side 19 inches long.

[A] 1410.8 in2

[B] 171.0 in2

[C] 2821.5 in2

[D] 256.0 in2

Answer 1

Is this the right formula
A=9/\[9/4 a ^{2}(180º/9)

Answer 2

You will have 9 triangles that all look like this



they will arrange to form a nonagon

Answer 3

find the area of 1 triangle, then multiply that area by 9

Answer 4

Oh ok

Answer 5

And what formula would I use for that?

Answer 6

A = 1/2 bh

Answer 7

yes

Answer 8

oh ok! And 19 would be the base, while the 16.5 is the height, correct?

Answer 9

correct, what area do you get?

Answer 10

Um, the final answer would be A right? But the area I got was 156.75

Answer 11

And then when I multiplied that by 9, I got 1210,75 which would round up to 1410.8

Answer 12

very good, you nailed it

Answer 13

Thank you!