If the interior angle of a regular polygon is 144°, then what is the number of its sides?
10
Given here are some figures.
Classify each of them on the basis of the following.
(a) Simple curve
(b) Simple closed curve
(c) Polygon
(d) Convex polygon
(e) Concave polygon
Solution: (a) Simple curves are: (1), (2), (5), (6) and (7).
(b) Simple closed curves are: (1), (2), (5), (6) and (7).
(c) Polygons are: (1), (2) and (4).
(d) Convex polygon is: (2).
(e) Convex polygons are (1) and (4).
If the exterior angle of a regular polygon is 72°, then what is the number of sides of the polygon?
5