Question

The sum of the angle measures of the polygon is 540. write and solve an equation to find the value of x

Answer 1

$\\ \sf\longmapsto 85+5x+5x+5x-10+5x+5=540$

$\\ \sf\longmapsto 5x+5x+5x+5x+85-10+5=540$

$\\ \sf\longmapsto 20x+80=540$

$\\ \sf\longmapsto 20x=540-80=460$

$\\ \sf\longmapsto x=\dfrac{460}{20}$

$\\ \sf\longmapsto x=23$