Question

A polygon has 11 sides. What is the sum of the measure of the interior angles of the polygon?

Answer 1

(n-2) x 180
(11-2)x180
9x180 =1620 degrees

Answer 2

But why? Can you explain where the formula 180(n-2) comes from?

Like everything in mathematics, it's better to understand where it comes from so you can rederive the formula if you forget.

Answer 3

i learnt it in sch. i don really know why o.O http://answers.yahoo.com/question/index?qid=20080505202850AAe8NIS

Answer 4

Take a triangle. It has n = 3 sides and it has a sum of angles of 180 degrees.

Now, can you see how to take two triangles and put them together to make a square (an example of a four-sided polygon).

Then the sum of the angles of the square is 2 times 180 degrees. It has a number of sides, n = 4.

Now, take the square and stick another triangle on it to make a 5-sided polygon. That will add another 180 degrees.

Hopefully it's not clear how this generalizes.

Answer 5

i guess its smth like this.