Year 4 · Shapes, Angles and Symmetry · Summary
Year 4 Shapes, Angles and Symmetry: summary and key words
Part of the Year 4 shapes, angles and symmetry chapter. Chapter overview · whole chapter on one page
Chapter summary
| Skill | Method |
|---|---|
| Turns | Whole turn = 4 right angles. Half turn = 2 (a straight line). Quarter turn = 1. Three-quarter turn = 3. Clockwise goes the way a clock goes. |
| Angles | Acute: smaller than a right angle. Right angle: a quarter turn. Obtuse: bigger than a right angle, smaller than a straight line. Compare with a paper corner. Arm length does not matter. |
| Perpendicular and parallel | Perpendicular lines meet at a right angle. Parallel lines never meet and stay the same distance apart. |
| Triangles | Equilateral: 3 equal sides. Isosceles: 2 equal sides. Scalene: none. Right-angled: one right angle. Tick marks show equal sides. |
| Quadrilaterals | Square, rectangle, rhombus, parallelogram (2 pairs of parallel sides), trapezium (exactly 1 pair), kite (2 pairs of equal sides next to each other). A square is a special rectangle. |
| Polygons | Pentagon 5, hexagon 6, heptagon 7, octagon 8, nonagon 9, decagon 10 sides. Regular: all sides and all angles equal. Sides = vertices. |
| Sorting | Carroll diagram: a table with yes and no. Venn diagram: both labels go in the overlap, neither goes outside the circles. |
| Lines of symmetry | Fold line where both halves match. Regular polygon: as many lines as sides. Rectangle 2, square 4, parallelogram 0. Turning does not change the number. |
| Complete a symmetric figure | Find each point’s partner: same distance from the mirror line, other side. Diagonal mirror line: row and column swap. |
Can you…?
- I can say how many right angles are in a quarter, half, three-quarter and whole turn.
- I can name acute, right and obtuse angles and a straight line.
- I can compare and order angles by size, even when the arms have different lengths.
- I can name equilateral, isosceles, scalene and right-angled triangles.
- I can name the six quadrilaterals and find parallel and perpendicular sides.
- I can name polygons with 5 to 10 sides and say if they are regular.
- I can sort shapes in Venn and Carroll diagrams and solve “Which shape am I?” riddles.
- I can find the lines of symmetry of shapes, letters and patterns, however they are turned.
- I can complete a symmetrical figure using a vertical, horizontal or diagonal mirror line.
Key terms
- Turn
- A movement round a point. Whole, half, quarter and three-quarter turns.
- Right angle
- A quarter turn. The corner of a book. Marked with a small square.
- Acute angle
- An angle smaller than a right angle.
- Obtuse angle
- An angle bigger than a right angle but smaller than a straight line.
- Straight line (angle)
- Two right angles, a half turn.
- Clockwise / anticlockwise
- The way a clock’s hands go / the opposite way.
- Perpendicular
- Meeting at a right angle.
- Parallel
- Lines that stay the same distance apart and never meet.
- Equilateral triangle
- A triangle with 3 equal sides.
- Isosceles triangle
- A triangle with 2 equal sides.
- Scalene triangle
- A triangle with no equal sides.
- Right-angled triangle
- A triangle with one right angle.
- Quadrilateral
- A shape with 4 straight sides.
- Rhombus
- A quadrilateral with 4 equal sides and no right angles.
- Parallelogram
- A quadrilateral with two pairs of parallel sides.
- Trapezium
- A quadrilateral with exactly one pair of parallel sides.
- Kite
- A quadrilateral with two pairs of equal sides next to each other.
- Polygon
- A closed flat shape with straight sides.
- Vertex
- A corner of a shape (plural: vertices).
- Regular polygon
- A polygon with all sides equal and all angles equal.
- Irregular polygon
- A polygon that is not regular.
- Venn diagram
- A sorting diagram made of circles.
- Carroll diagram
- A sorting diagram that is a table with yes and no.
- Line of symmetry
- A fold line where the two halves of a shape match exactly.
- Mirror line
- The line a shape is reflected in.
- Reflection
- A flip of a shape in a mirror line.