Quadrilateral: Interior Angles
How to solve the interior angles of a quadrilateral: formula, 1 example, and its solution.
Formula
m∠1 + m∠2 + m∠3 + m∠4 = 180
∠1, ∠2, ∠3, ∠4: Interior angles of a quadrilateral
Example
Solution
Solution (Detail)
These four angles
are the interior angles of the quadrilateral.
So
[5x + 30] + [12x] + [3x + 40] + [90] = 360.
5x + 12x + 3x = 20x
30 + 40 + 90 = 160
So 20x + 160 = 360.
Move +160 to the right side.
Then 20x = 200.
Divide both sides by 20.
Then x = 10.
So x = 10 is the answer.