Find the measure of angle E.

Question

http://static.k12.com/eli/bb/811/7537/0/2_36640_44211/7537/cfcbab7622b25115e3996826ebe54350776a6601/media/a0fb44a9ac3761c0d89bd1c3ffa513c508eb78bf/mediaasset_650483_1.gif

help please i still mix the formulas

Answer 1

Hint:

The inner angles of an $n$-gon add up to $(n-2)\pi$

From there, can you find $x$?

Answer 2

For an $n$-sided polygon, the sum of the interior angles is $180(n - 2)$. So I suggest that you try adding up all of those angle measures, setting it equal to $180(n - 2)$, and then solve for $x$. Afterwards, you'll just need to plug that value of $x$ into the angle measure of $E$.

Answer 3

Try splitting the nonagon (the 9-sided polygon in the diagram) into triangles. If a triangle has $180^\circ$, a rectangle $360^\circ$, and a pentagon $540^\circ$, how many degrees would a nonagon have? are the angles measured in degrees or radians?