Checking and securing understanding of advanced angle facts | Maths

Starter quiz

Two lines are ______ if they are straight lines that are always the same (non-zero) distance apart.

'parallel' ✓
A __________ is a line, line segment, or ray that intersects through two or more lines at distinct (different) points.

tangent

transformation

translation

transversal ✓
In which image(s) is the protractor in a correct position to measure the marked angle?
The size of ∠AED is 105°. Therefore the size of the acute angle ∠DEC is ______°.

'75' ✓
The size of ∠AED is 105°. Therefore the size of the reflex angle ∠DEA is ______°.

'255' ✓
The size of ∠AED is 105°. Therefore the size of the obtuse angle ∠CEB is ______°.

'105' ✓

Exit quiz

The angle that is corresponding with angle $c$ is angle ______.

'g' ✓
The angle that is alternate with angle $c$ is angle ______.

'e' ✓
The angle that is co-interior with angle $c$ is angle ______.

'f' ✓
The angle that is vertically opposite angle $c$ is angle ______.

'a' ✓
Angles $d$ and $e$ are __________.

alternate

co-interior ✓

corresponding

vertically opposite
Angles $a$ and $g$ are __________.

alternate ✓

co-interior

corresponding

vertically opposite

Worksheet

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Lesson Details

Key learning points

Corresponding angles are equal if they are on parallel lines and the same side of the transversal.
Alternate angles are equal if they are on parallel lines and the opposite sides of the transversal.
Supplementary co-interior angles sum to 180°

Common misconception

Alternate angles are always equal to each other.

Alternate angles are equal when a transversal intersects parallel lines. If the transversal intersects a pair of lines that are not parallel then the alternate angles will not be equal.

Keywords

Transversal - A transversal is a line, line segment, or ray that intersects through two or more lines at distinct (different) points.
Corresponding angles - Corresponding angles are a pair of angles at different vertices on the same side of a transversal in equivalent positions.
Alternate angles - Alternate angles are a pair of angles both between or both outside two line segments that are on opposite sides of the transversal that cuts them.
Co-interior angles - Co-interior angles are on the same side of the transversal line and in between the two other lines.