Geometry — NSW Year 10 Core Maths
Angles and polygons, then similar figures and similar triangles. Three subtopics and 60 practice questions with worked solutions, aligned to NESA MA5-GEO-C-01 and MA5-GEO-P-01.
Geometry in NSW Year 10 Core
Geometry in Year 10 Core begins by revising angle facts and extending them to polygons, then uses the properties of similar shapes and similar triangles to find unknown sides and angles.
The three subtopics below follow that order. Geometry is one of the 11 topics in NSW Year 10 Maths Core and draws on NESA outcome MA5‑GEO‑C‑01, the Path outcome MA5‑GEO‑P‑01, and Stage 4 angle work (MA4‑ANG‑C‑01). Similar triangles lead straight into trigonometry. Congruent triangles and networks are studied in Year 10 Advanced.
Subtopics
Geometry: common questions
What is the angle sum of a polygon?
The interior angles of a polygon with \(n\) sides add to \((n - 2) \times 180^\circ\). A hexagon has \(6\) sides, so its angles add to \(4 \times 180^\circ = 720^\circ\).
What is the difference between congruent and similar figures?
Congruent figures are identical in shape and size. Similar figures have equal matching angles, but one is an enlargement or reduction of the other, so their matching sides are in the same ratio.
How do you find the scale factor of similar figures?
Divide a side of the image by the matching side of the original. If a 4 cm by 6 cm rectangle becomes 10 cm by 15 cm, the scale factor is \(\frac{10}{4} = 2.5\).
How do you show that two triangles are similar?
Use one of the four tests: all three pairs of matching angles are equal (AAA), all three pairs of matching sides are in the same ratio (SSS), two pairs of sides are in the same ratio and the angles between them are equal (SAS), or, for right-angled triangles, the hypotenuses and one other pair of sides are in the same ratio (RHS).
Which NESA outcomes cover Year 10 Core geometry?
Similar figures and scale drawings come under MA5‑GEO‑C‑01, and the angles of polygons belong to the Path outcome MA5‑GEO‑P‑01.