Find the number of sides when given the sum of interior angles

Maths

The sum of interior angles of a polygon is 720º. How many sides does the polygon have?

The sum of interior angles of a polygon is 2880º. How many sides does the polygon have?

The sum of interior angles of a regular polygon is 3960º. What is the size of each interior angle of the regular polygon?

The sum of interior angles of a regular polygon is 5040º. What is the size of each exterior angle of the regular polygon?

What is the sum of interior angles of a 20-sided shape?

What is the sum of interior angles of a 9-sided shape?

What is the size of each interior angle in a regular octagon?