All concepts combined
Primary 5 Angles study guide: the whole chapter, step by step
About this subtopic
This mixed practice stop brings together 5 topics from Primary 5 Angles: Straight lines and opposite angles, Angles at a point, Across the join, Following the parallel route, The fold. Nothing on the question says which topic it comes from, so choosing the method is part of the skill.
Practice questions with worked solutions
Question 1 is free to try. The other 2 open in the free trial, each with its full working.
Print this subtopic · included with a plan
2 more questions, each with its full working.Answers checked, progress kept, wrong ones come back in revision. No card needed.
Start the 7-day free trialQuestion 1 of 3 · Intermediate · free to tryABCD is a rectangular piece of paper. A, P and B lie on the straight edge…ABCD is a rectangular piece of…
ABCD is a rectangular piece of paper. A, P and B lie on the straight edge AB, and the line PR is drawn on the paper with R on the edge DC. Angle APR = 100°. The corner B is folded along the crease PQ, where Q is on the edge BC, so that the edge PB lies exactly along PR and B lands at B'. The figure shows the paper after the fold, and it is not drawn to scale. Find angle APQ.
Show the working and the answer
Working
- ∠RPB = 180° − 100° = 80° (angles on a straight line APB)
- ∠QPR = ∠QPB (folded angles are equal)
- ∠QPB = 80° ÷ 2 = 40° (the two equal angles share ∠RPB)
- ∠APQ = 180° − 40° = 140° (angles on a straight line APB)
Answer: 140°
For parents
How do you find a route in P5 angles mixed practice questions?
Each question here needs a chain of angle facts, and the figure does not say where to start.
What your child learns here
Each question here needs a chain of angle facts, and the figure does not say where to start. A fold makes two angles equal, a square joined to an isosceles triangle shares a corner, and a trapezium with a line drawn from one corner hides an isosceles triangle. Your child finds the first angle the figure gives away and carries it across. The facts come from the Primary 5 Angles outcomes, with triangles and four-sided figures from the same year.
- Angles on a straight line add up to 180°, and angles at a point add up to 360°.
- A fold makes the angle on one side of the crease equal to the angle on the other side.
- The angles of a triangle add up to 180°, and an isosceles triangle has two equal angles opposite its equal sides.
- Between a pair of parallel sides, the two angles on the same side add up to 180°.
- Write the reason beside each angle, so the next step uses an angle that is known, not one that only looks right.
Does the answer make sense?
In the square and triangle question, angle ABF is made of the square's 90° and one base angle of the triangle, so it must be more than 90°. The triangle's top angle is 52°, its two equal base angles are 64° each, and 90° plus 64° gives 154°.
How to practise these questions
All three questions are Intermediate. One folds the corner of a rectangle so that an edge lies along a line already drawn, and the crease halves the angle between them. One joins a square to an isosceles triangle along a side and gives one angle outside the figure on a straight line. One draws a line from a corner of a trapezium and gives two angles at that corner. Each needs three or four steps. Ask your child to mark every angle they find on the figure as they go, with its reason, and to check each new angle against the straight line or angle sum it came from.
Questions parents ask
How does my child know where to start? Look for an angle that can be found in one step: one on a straight line beside a given angle, or one at a fold. That angle usually opens the next triangle.
Can my child measure the angles instead? No. These figures are not drawn to scale, so the angles are found from the given angles and the properties of the shapes.
Does my child have to write a reason for each step? It is a good habit. A short reason in brackets, such as angles on a straight line, shows which fact was used and makes any slip easy to find.