The diagram shows a regular pentagon with side $2 \mathrm{cm}$. $O$ is the centre of the pentagon.
Find angle $AOE$.

   

The diagram shows a regular pentagon with side $2 \mathrm{cm}$. $O$ is the centre of the pentagon.
Find angle $AOM$.

   

The diagram shows a regular pentagon with side $2 \mathrm{cm}$. $O$ is the centre of the pentagon.

Use trigonometry on triangle $AOM$ to find the length $OM$.

The diagram shows a regular pentagon with side $2 \mathrm{cm}$. $O$ is the centre of pentagon.

Find the area of triangle $AOM$

Write the following in the form of another angle between $0°$ and $180°$.

$-\cos 120°$