Parallel lines and angles in a triangle  Image

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Parallel lines and angles in a triangle

In this activity students find the missing angle in a triangle and identify angles on parallel lines.

Additional details

Year level(s) Year 7
Audience Teacher
Purpose Content knowledge, Teaching resource
Teaching strategies and pedagogical approaches Feedback
Keywords Angles, Parallel, Co-interior, Alternate, Triangle, Interior

Curriculum alignment

Strand and focus Space
Topics Angles and geometric reasoning
AC: Mathematics (V9.0) content descriptions
Identify corresponding, alternate and co-interior relationships between angles formed when parallel lines are crossed by a transversal; use them to solve problems and explain reasons


Demonstrate that the interior angle sum of a triangle in the plane is 180° and apply this to determine the interior angle sum of other shapes and the size of unknown angles

Numeracy progression Understanding geometric properties (P6)

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