In a pentagon, two angles are 40° and 60° and the rest are in the ratio 1 : 3 : 7. Find the biggest angle of the pentagon.

Each interior angle of a regular polygon is double of its exterior angle, the number of sides in the polygon is.

1. 3

2. 4

3. 6

4. 8

The sum of all interior angles of a regular polygon is equal to sum of all its exterior angles. The number of sides in the polygon is:

1. 4

2. 5

3. 6

4. 8