Question

Can anyone explain #4 on how to do it

Answer 1

$\frac{(n-2)\cdot180}{n}=144\\ 180n-360=144n\\ 36n=360\\ n=10$

It's decagon.

Answer 2

Here is the formula for find the one inside of the polygon: 
(n-2).180/n (n shows how many sides does polygon have)
so now we can solve the equation==== (n-2).180/n=144
1144n=(n-2).180
144n=180n-360
360=36n
n=10 
so we call it decagon :)