Question

The sum of interior angles of a regular polygon is 1980 degrees. How many sides does the polygon have?

Answer 1

The formula for interior angle sum is 180(n - 2).

Backtrack it from that.

180(n - 2) = 1980.

1980 / 180 = 11 = n - 2.

11 + 2 = 13 = n.

The polygon has 13 sides.

Explanation:

Answer 2

The formula for interior angle sum is 180(n - 2).
Backtrack it from that.
180(n - 2) = 1980.
1980 / 180 = 11 = n - 2.
11 + 2 = 13 = n.
The polygon has 13 sides.