T

2D Shapes & Their Features

Maths · Y3 Shape
Year 3
Lesson Guide
Explanation
2D shapes are flat, and we describe them by counting two things: SIDES (the straight edges) and CORNERS (the pointy places where sides meet — maths people call them vertices). A triangle has 3 sides and 3 corners; a rectangle has 4 and 4. Neat fact: in these shapes, the counts always match!
Your Turn
Trace a shape in the room (a window, a book cover). Count its sides and corners by touching each one.
Watch Out
Count each side ONCE — run your finger along each edge as you count so you don't loop around twice.
Explanation
Any flat shape with 4 straight sides is a QUADRILATERAL ('quad' means four). The family includes squares (4 equal sides, square corners), rectangles (opposite sides equal, square corners) and parallelograms (like a rectangle pushed sideways). Surprise: a square is actually a special rectangle — it just has all its sides equal!
Your Turn
Hunt for 3 quadrilaterals around you. Which are squares, which rectangles? (Screens, tiles, windows, books…)
Watch Out
Tilting a square doesn't turn it into a 'diamond' — it's still a square! Shapes keep their names when they turn.
Explanation
Keep adding sides and the names follow Greek numbers: PENTAgon has 5 sides, HEXAgon has 6, OCTAgon has 8 — remember the octopus with 8 legs! You've seen them around: a STOP sign is an octagon, honeycomb cells are hexagons, and home plate in baseball is a pentagon.
Your Turn
Draw a hexagon (it can be wobbly — just 6 straight sides!). Count its corners. Check: 6.
Watch Out
The shape doesn't need to be perfect and even — ANY closed shape with 6 straight sides is a hexagon.
Explanation
Shapes come in tidy and wild versions. A REGULAR shape has all sides and all corners equal — the neat pentagon you'd draw for a badge. An IRREGULAR shape is stretched or lopsided — but if it has 5 straight sides, it's STILL a pentagon! Names come from counting, not from prettiness. Always count the sides before naming.
Your Turn
Draw a really wonky 6-sided shape. What is it called? Check: an (irregular) hexagon — the count is all that matters.
Watch Out
Tests love showing weird-looking shapes. Ignore the look, COUNT the sides, and the name follows.
Explanation
Time to be a shape detective! Clues describe sides and corners; you name the shape. '4 equal sides, 4 square corners' — square. '6 sides, bees build with me' — hexagon. '3 sides with 2 equal' — a triangle (the two-equal-sides kind is called isosceles — a fancy word to impress people with). Detective hats on: quiz and exercises await!
Your Turn
Make up a shape riddle for someone at home. If they can't guess it, your clues need more detail — that's the skill!
Watch Out
A good clue mentions BOTH sides and corners. Just "I have 4 sides" fits squares, rectangles AND parallelograms.
Step 1: Introduction
Step 1 of 5
Count sides and corners (vertices) triangle: 3 sides, 3 corners rectangle: 4 sides, 4 corners Straight edges = sides · points where sides meet = corners (vertices) Sides and corners always match: 3 and 3, 4 and 4, 5 and 5…
All 4-sided shapes are quadrilaterals square 4 equal sides rectangle opposite sides equal parallelogram a pushed-over rectangle Quad = four. Any shape with 4 straight sides belongs to the family. A square IS a special rectangle — all sides equal!
More sides, more names pentagon 5 sides hexagon 6 sides octagon 8 sides penta = 5 · hexa = 6 · octa = 8 (like an octopus's 8 legs!) A STOP sign is an octagon. Honeycomb cells are hexagons.
Same family, different looks regular pentagon all sides & corners equal irregular pentagon still 5 sides — count them! The NAME comes from counting sides — not from looking pretty.
Guess the shape from clues 🔍 "I have 4 equal sides and 4 square corners." A square! "I have 6 sides. Bees build with me." A hexagon! "I have 3 sides, and 2 of them are equal." A triangle (an isosceles one — two matching sides!) Now be the detective in the quiz and exercises!
Was this lesson helpful? Rate this Course
Discussion
Loading comments...