CoreIn almost every paper that tests this subjectAbout 60 seconds a question in the test
The big idea
Perimeter is the distance around a shape; area is the space inside it, measured in square units.
Angle facts: angles on a straight line add to 180°, angles around a point add to 360°, angles in a triangle add to 180°, and in a quadrilateral they add to 360°.
Tips that save marks
Split compound shapes into rectangles, or find the big rectangle and subtract.
Label missing side lengths before calculating perimeter.
Always include units (cm, cm², °).
A worked example
A triangle has angles 47° and 68°. Find the third.
47 + 68 = 115.
180 − 115 = 65°.
Now try five
Try each one before you look at the answer: answering from memory is what makes it stick. Tap an option to check it. Most children get three or four right at first; five out of five means move on to the next topic.
Question 1Aim for about 60 seconds
How many edges does a pentagonal prism have?
Show the worked answer
Answer: E, 15
How to work it out
Edges are the lines where two faces meet.
A pentagonal prism has 7 faces, 15 edges and 10 vertices.
Count the hidden ones at the back too.
Why the other options are wrong
A (10): This is the number of vertices, not edges.
B (12): Some are hidden at the back: they still count.
C (17): One or more have been counted twice.
D (7): This is the number of faces, not edges.
Question 2Aim for about 60 seconds
A rectangle is 10 cm long and 5 cm wide. What is its area?
Show the worked answer
Answer: A, 50 cm²
How to work it out
Area = length × width = 10 × 5 = 50 cm².
Question 3Aim for about 60 seconds
How many lines of symmetry does this regular pentagon have?
Show the worked answer
Answer: B, 5
How to work it out
A line of symmetry folds the shape exactly onto itself.
A regular pentagon has 5.
Why the other options are wrong
A (7): Some of these folds do not make the two halves match: check each one.
C (4): One line missing: try the fold the other way.
D (6): One too many: fold along it and the halves do not match.
E (0): Try folding it down the middle: the halves match.
Question 4Aim for about 60 seconds
A rectangle is 15 cm long and 13 cm wide. What is its area?
Show the worked answer
Answer: B, 195 cm²
How to work it out
Area = length × width = 15 × 13 = 195 cm².
Question 5Aim for about 60 seconds
A square has a perimeter of 84 cm. How long is each side?
Want a plan built around the topics your child finds hardest?
Prism starts with a free assessment across maths, English, verbal and non-verbal reasoning, then builds a weekly plan for your target schools. Parents follow progress free.