Angles & 2D Shapes — Year 7 Revision Notes
These notes cover the key angle facts, classifying triangles and quadrilaterals, and setting out clear geometric reasoning.
Angle facts
Angles on a straight line add up to 180°, angles at a point add up to 360°, and angles in a triangle add up to 180°. Use these to find missing angles, giving a reason each time.
Key Facts & Formulas
- straight line = 180°
- at a point = 360°
- triangle = 180°
Tips
- Write a reason next to every angle you find.
- Vertically opposite angles are equal.
Classifying triangles
An equilateral triangle has three equal sides and three 60° angles; an isosceles triangle has two equal sides and two equal angles; a scalene triangle has all sides and angles different. A right-angled triangle contains a 90° angle.
Key Facts & Formulas
- equilateral angles = 60°
Tips
- Do not assume a triangle is isosceles from the picture — use the marks given.
- Equal sides are shown with dashes on the diagram.
Classifying quadrilaterals
Quadrilaterals have four sides and their angles add up to 360°. A square has four equal sides and four right angles; a rectangle has equal opposite sides and four right angles; a parallelogram has two pairs of parallel sides.
Key Facts & Formulas
- quadrilateral angles = 360°
Tips
- Learn the properties of each special quadrilateral.
- Parallel sides are shown with arrow marks.
Revision Checklist
- I can use angle facts on a line, at a point and in a triangle
- I can give a reason for each angle I find
- I can classify triangles by their sides and angles
- I can describe the properties of common quadrilaterals
Frequently Asked Questions
Do the angles in any quadrilateral add up to 360°?
Yes. Every four-sided shape has interior angles that add up to 360°, which you can show by splitting it into two triangles.
Build strong foundations in Angles & 2D Shapes
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