Answer:
Area of nonagon = 1044.6 square millimetres.
Explanation:
Let side of the nonagon is a
Given:
The perimeter of nonagon is 117 millimetres
![perimeter=9a](https://img.qammunity.org/2020/formulas/mathematics/middle-school/43yabgx0ighnw86lyf1o9cqfr1exr1c0yo.png)
Put the perimeter value in above equation
![a=(117)/(9)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9lwd7sbxduw012n45670jwtg80gytncx57.png)
![a=13](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qc0i8qrj4n6mn8em6mv2prwpqwgqgi2yt8.png)
So the side of the nonagon is 13
The area of the nonagon is .
![A=(9)/(4) a^(2) cot((180)/(9))](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e0runzymuw8euhq1qfdpmr8o7ts47xvadx.png)
where a is side of the nonagon.
Put value of side in above equation
![A=(9)/(4) 13^(2) cot(20)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/pj1jmsofgn6pxemr37fthhzsljuao3xiz6.png)
![A=(9* 169)/(4)* 2.747}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/4sdba2fg1qgur5hx32ssbthp3bpmljp6u7.png)
![A=(1521)/(4)* 2.747}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dvb029y50mwd8pkikvxfjz8wxmxmf1utwu.png)
![A=380.25* 2.747}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/274wrnu8ue77q1ho2rr9zbxwii17krebah.png)
![A=1044.55](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8qihcbh9qz490wfh2rb5xgwysy8th39d5k.png)
Therefore, the area of the nonagon is 1044.6 square millimetre.