Answer:
x = 70
Step-by-step explanation:
The sum of the internal angles of a polygon is (n-2)*180. This figure has 6 sides, so the sum of its internal angles is720, so...
x + 2x + 2x + (2x - 10) + (x+30) + (x+70) = 720 simplifies to
x + 2x + 2x + 2x - 10 + x + 30 + x + 70 = 720 gather like terms
9x + 90 = 720, subtract 90 to both sides
9x = 630, divide by 9, get
x = 70
Check the answer
70 + 2*70 + 2*70 +2*70-10 +70+30 + 70+70 is
70 + 140 + 140 + 130 + 100 + 140 or
210 + 270 + 240 or
480 + 240 = 720, check
