# If the sum of interior angle measures of a polygon is 900, how many sides does the polygon have?

##### 1 Answer
Dec 19, 2015

the polygon is *heptagon (7-sided polygon)

#### Explanation:

Sum of interior angles is $180 \left(n - 2\right)$

Since sum is $= 900$,

$900 = 180 \left(n - 2\right)$

$\frac{900}{180} = \frac{180 \left(n - 2\right)}{180}$

$\frac{900}{180} = \frac{\cancel{180} \left(n - 2\right)}{\cancel{180}}$

$5 = n - 2$

$5 + 2 = n$

$7 = n$