Answer:
x ≈ 41
Explanation:
All the angles in a quadrilateral add together to equal 360°
So set up the equation:
a + b + c + d = 360°
Now fill in the values we know:
x + _ + 4x + 2x - 10 + 85 = 360
7x + 75 = 360
Now subtract both sides by 75:
7x + 75 - 75 = 360 - 75
7x = 285
Divide both sides by 7:
7x / 7 = 285 / 7
x = 40.714
Round:
x = 41
Now to check our answer, substitute 41 for x in the equation:
(41) + _ + 4(41) + 2(41) - 10 + 85
(41) + 164 + 82 - 10 + 85 = 362
The answer is close to 360, so we know it is correct