| Example 1 | - Two parallel lines are cut by a transversal. A corresponding angle is (3x + 10)°
- and the other corresponding angle is 100°. Find x
| parallellinestransversalcorresponding |
| Solution | - The angles are corresponding
- so they are equal: 3x + 10 = 100
- so 3x = 90 and x = 30
| anglescorrespondingequal |
| Example 2 | Two parallel lines are cut by a transversal. The co-interior angles measure 2x° and 3x°. Find each angle | parallellinestransversalinterior |
| Solution | - 2x + 3x = 180
- so 5x = 180 and x = 36. The angles are 72° and 108°. Check: 72 + 108 = 180
| anglesCheck |
| Example 3 | Two parallel lines are cut by a transversal. The alternate angles measure (x + 20)° and (2x − 50)°. Find the angle | parallellinestransversalalternate |
| Solution | - The angles are alternate
- so they are equal: x + 20 = 2x − 50
- so x = 70. The angle is 70 + 20 = 90°. Check: 2 × 70 − 50 = 90
| anglesalternateequalangle |