$\"\"$

The given angle is $\"\"$ ; $\"\"$

Adjacent angles that form a straight angle are supplementary.

So, $\"\"$ are supplementary angles.

If the two angles are supplementary angles then their sum is $\"\"$ .

$\"\"$ (Sum of supplementary angles is $\"\"$ )

$\"\"$ (Subtract $\"\"$ from each side)

$\"\"$ (Apply commutative property of addition: $\"\"$ ) \ \

$\"\"$ (Apply additive inverse propetry: $\"\"$ ) \ \

$\"\"$ (Apply additive identity property: $\"\"$ ) \ \

$\"\"$ (Subtract: $\"\"$ ) $\"\"$

The angle $\"\"$ .