Step-by-step explanation:
I'm going to assume you meant to write
in the equation as +1 - 1 wouldn't make much sense since they would just cancel out.
a. 
b. 
c. 
Answer:
20-gon
Step-by-step explanation:
First we start with the formula to find what the sum of angles will be if we know the number of sides.
S=(n-2)*180 where S is the sum of angles and n is the number of sides.
Normally you'd plug in n to find S, but you can do the opposite too.
3240=(n-2)*180
Let me know if you need help working it from here.
Answer:
$33 for 11 packs of paper
Look at the picture.

For XY and ZX use the Pythagorean theorem.


The perimetero fo XYZ:

Answer:
hope this helps you look it once.