math
posted by Donna on .
A multiple choice answers for the question. What is the measure of the dent angle for a starshaped polygon with 20 points and a dent angle of 12 degrees?
Asnwers are; 30 degrees, 50 degrees, 60 degrees, 90 degrees. How do I find the answer?

The angle at the tip of the star's points is called the point angle, and the angle subtended by two adjacent sides between two points is the dent angle.
In this case, the point angle, p, is 12° and there are 20 points (=n) in the star.
The dent angle can be obtained by:
D=(360/n)+p
=(360/20)+12
= 30 °.