Choose the regular polygon that has interior angles with a sum of 900 degrees.

A triangle has 3 sides, the total interior angels sum to 180 degrees.

A square has 4 sides, the total interior angels sum to 360 degrees.

A pentagon has 5 sides, the total interior angels sum to 540 degrees.

Do you see a trend?

Answer:

The (s) sum of interior angles equals the (n) number of sides, minus 2, times 180.

This is written as

s = (n - 2) * 180

If we put in 900 for s, we get

900 = (n - 2) * 180

5 = n - 2

n = 7

A polygon with 7 sides is called a Heptagon.