# Inscribed Quadrilateral

How to solve the interior angle of an inscribed quadrilateral: formula, 1 example, and its solution.

## Formula

For an inscribed quadrilateral,

the opposite interior angles are supplementary.

m∠1 + m∠2 = 180

m∠1' + m∠2' = 180

## Example

Solution

Solution (Detail)

The given quadrilateral

is an inscribed quadrilateral.

xº and 100º are the opposite interior angles.

So [x] + [100] = 180.

Move +100 to the right side.

Then x = 80.

The other two angles,

70º and yº,

are the other opposite interior angles.

So [70] + [y] = 180.

Move 70 to the right side.

Then y = 110.

x = 80

y = 110

Write the x and y values below.

So

x = 80

y = 110

is the answer.