# Year 9: Angles, pairs of lines, and 2D shapes on the Cartesian plane

TIMSS items involve parallel and perpendicular lines, and a range of 2D shapes, including circles, triangles, quadrilaterals, and other polygons. Students are expected to identify and construct angles, and pairs of lines, and to solve problems using the properties of 2D shapes (e.g. symmetry, sum of internal angles). Students solve problems involving perimeters and areas, and Pythagoras Theorem. The Cartesian Plane is used frequently in items.

These units of work will improve students' fluency with angles, parallel and perpendicular lines, and 2D shapes:

Students will also benefit from working independently or collaboratively on the following student e-ako on the Geometry and Measurement pathways (information about e-ako maths):

• G5.10: Angle properties of polygons
• G5.20: Angle properties of parallel lines
• G5.30: Finding the area of a regular polygon
• M5.1: Comparing diameter and perimeter of circles, and calculating speed
• M5.6: Learning about Pythagoras' Theorem