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G1.2 • Sec 1 MOE
Geometry & Measurement

Angles & Parallel Lines

Use angle properties with parallel lines and a transversal.

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Learning objectives

  • Identify corresponding, alternate, and interior angles
  • Calculate unknown angles
  • Apply properties of angles on a straight line
Learning methods:CRAI-We-YouSpaced reviewRetrievalMetacognition

Brain warm-up (try before we teach)

Try first, then learn step by step

Two angles on a straight line are 110° and x°. Find .

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Foundation — I Do → We Do → You Do

1
I Do — Learn
Step 1 of 4

Angle facts

  • Angles on a straight line sum to 180°
  • Vertically opposite angles are equal
  • Corresponding angles (parallel lines) are equal
  • Alternate angles (parallel lines) are equal
2
I Do — Learn
Step 2 of 4

Worked example

Two parallel lines are cut by a transversal. One corresponding angle is 65°.

The corresponding angle on the other parallel line is also 65°.

3
We Do — Guided
Step 3 of 4

Guided: Straight line

Two angles on a straight line are 110° and x°. Find .
4
You Do — Practice
Step 4 of 4

Practice: Alternate angles

Alternate angles are equal. If one alternate angle is 48°, find the other.