Math Problem... Please help!!!?

Question

the expressions (3x+63) and (7x-45) represent the measures of two angles of a regular decagon.

Find the measure of an angle of the decagon.

please help me with this problem ...

Answer 1

A decagon has 10 sides.  The formula for figuring out the measure of each angle is: "Sum of the interior angles of a polygon = (N - 2) x 180°"

For a 10 sided shape, you would have (10-2)*180°

8*180=1440

That is the total for all 10 interior angles.  Therefore each one is 1440/10=144

So set (3x+63) and (7x-45) both equal to 144.  

3x+63=144

3x=81

x=27

7x-45=144

7x=189

x=27