Question

Please answer the following:

Answer 1

The sum of all interior angles in a polygon is
180(n - 2), where n = the number of sides in the polygon.

now, notice this figure above, it has 5 sides, namely is a PENTAgon, so the sum of all its interior angles is 180( 5 - 2), or 540, therefore

$\bf (4x)~+~(3x+15)~~+~~(4x-25)~~+~~(3x+25)~~+~~(2x-3)=540 \\\\\\ 16x+12=540\implies 16x=528\implies x=\cfrac{528}{16}\implies x=33$