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

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

anonymous · Answer

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

jim_thompson5910 · Answer

You will have 9 triangles that all look like this

|dw:1433031577045:dw|

they will arrange to form a nonagon

jim_thompson5910 · Answer

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

anonymous · Answer

Oh ok

anonymous · Answer

And what formula would I use for that?

anonymous · Answer

A = 1/2 bh

jim_thompson5910 · Answer

yes

anonymous · Answer

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

jim_thompson5910 · Answer

correct, what area do you get?

anonymous · Answer

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

anonymous · Answer

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

jim_thompson5910 · Answer

very good, you nailed it

anonymous · Answer

Thank you!