Mini Minds Hub · Free printable
Area of Triangles: Free Printable Worksheet for Year 6
- ForYear 6
- StageKey Stage 2
- CostFree
- FormatPrintable PDF
Area of Triangles is a free printable maths worksheet for Year 6 (ages 10 to 11). Children are given the base and height of a triangle and use half base times height to find its area. It takes about 15 minutes, needs only a pencil, and page 2 gives the grown up notes, help, a stretch idea and the answers.
It comes from the Mini Minds Hub, the free library of printables from Jaques of London, the British games and toy company that has been making games for families since 1795. Print both pages, give page 1 to the child and keep page 2 for yourself. Black and white printing works well.
What is on the sheet
Each numbered question gives the base and the height of a triangle in centimetres. Children write the area in the space beside it. They multiply the base by the height, then halve the result. The numbers vary, so some children will halve first and others will halve last. Squared paper is handy for drawing each triangle if a picture helps.
- Base 6 cm, height 4 cm. Area = ___
- Base 10 cm, height 3 cm. Area = ___
- Base 8 cm, height 5 cm. Area = ___
- Base 12 cm, height 6 cm. Area = ___
- Base 4 cm, height 9 cm. Area = ___
- Base 7 cm, height 4 cm. Area = ___
- Base 10 cm, height 10 cm. Area = ___
- Base 14 cm, height 3 cm. Area = ___
A worked example with different numbers
A triangle has a base of 16 cm and a height of 11 cm. What is its area?
These numbers are different from every question on the sheet. The example shows two ways to use the same idea.
Method 1: rectangle, then halve- Picture a rectangle with the same base and height: 16 cm by 11 cm.
- Multiply: 16 × 11 = 176.
- The triangle is half of that rectangle. Half of 176 is 88.
- Halve the base: 16 ÷ 2 = 8.
- Multiply by the height: 8 × 11 = 88.
- Both methods give the same answer, so the order does not change the result.
Ways to build understanding
Start with the rectangle
Before using the rule, ask children to draw a rectangle on squared paper and find its area by multiplying. Then draw a triangle with the same base and height inside it. Seeing the link makes the rule easier to remember.
Find the height first
The height is the straight line from the top point down to the base, meeting the base at a right angle. Ask children to draw it in with a ruler before they calculate.
Count squares to check
On squared paper, children can count whole and part squares inside a triangle and compare with the rule. The two answers should be close.
Try a leaning triangle
Draw a triangle that leans to one side. Ask where the height is now. It is still the upright distance, not the slanted side.
Why half base times height works
Area is the amount of flat space inside a shape. We measure it in square units, such as square centimetres. For a rectangle, we multiply the length by the width. Children in Year 6 build on this when they move on to triangles and meet the idea that a formula is a short rule for finding a measurement.
A triangle has the same area as half of a rectangle with the same base and height. That is why we multiply base by height and then halve. The height must be measured at a right angle to the base. The slanted side of a triangle is usually longer than the height, so it should not be used in the calculation.
Skills and curriculum link
- Area of triangles
- Using a formula
- Multiplication
- Halving
- Square units
- Explaining reasoning
This sheet supports the area below. It is matched to the published England framework. Please check it against your own school plan.
| Framework | Subject or area | Strand | Year |
|---|---|---|---|
| National Curriculum (England) | Maths | Measurement | Year 6 |
What children will be able to do
- I can find the base and height of a triangle.
- I can use base times height, then halve it.
- I can write the answer in square units.
Helpful ideas for grown ups
- Area and perimeter are differentArea is the space inside a shape. Perimeter is the distance around the edge. Children sometimes mix them up, so say which one you are finding.
- Square units matterArea is written in square units, such as cm². A length is written in cm. Writing the unit helps children show what they have found.
- Halving can come first or lastMultiplying then halving gives the same result as halving one number then multiplying. Let children choose whichever feels easier.
- Height is not always a sideThe height is the upright distance from the base to the top point. Ask children to show it with a ruler or a finger before they calculate.
Key words
- BaseThe side of the triangle that the height is measured from.
- HeightThe distance from the base up to the top point, measured at a right angle to the base.
- AreaThe amount of flat space inside a shape.
- Square centimetreA square with sides of 1 cm. We use it to measure area.
- FormulaA short rule that tells you how to work something out.
- HalveSplit into two equal parts. Half of 20 is 10.
How to use it
- Print both pages. Page 1 is for the child. Keep page 2, which has the notes and answers.
- Read the first question together. Ask the child to say which number is the base and which is the height.
- Let them draw the triangle on squared paper if it helps, then multiply and halve.
- Check against page 2. Ask, "Why did you halve?" The reasoning matters as much as the answer.
- Come back to it another day and redo any tricky questions. Repeating a familiar sheet builds confidence.
Help, stretch and game ideas
If it feels too hard
Draw a rectangle with the same base and height on squared paper, find its area, then halve it. Start with the questions where halving feels easiest. Say each step aloud: multiply, then halve. Come back to the others later.
To stretch confident children
Find the missing height when the base is 8 cm and the area is 24 cm squared. Think about the matching rectangle first. Then make up your own puzzle with a missing base or height and swap it with a friend.
Make it a game
Draw a triangle on squared paper and mark its base and height. Challenge a friend to find its area. Swap roles. Score a point for each correct area and a bonus point for explaining why you halve. First to five points wins.
Mistakes to watch for
Watch forA child multiplies base by height and forgets to halve.
Try thisAsk, "Is the triangle bigger or smaller than the rectangle?" Draw the rectangle round it and show that the triangle fills only half.
Watch forA child uses the slanted side as the height.
Try thisDraw the height with a ruler from the top point straight down to the base, at a right angle. Compare its length with the slanted side.
Watch forA child writes the answer in cm instead of square units.
Try thisRemind them that area counts squares. Ask them to write cm² and say it as square centimetres.
Talk about it
- How is a triangle like half a rectangle?
- Which side is the height, and how do you know?
- Would you halve first or last? Why?
- What would happen to the area if the base got twice as long?
- Where might someone need to find the area of a triangle in real life?
- What makes a question easy or tricky for you?
Take it off the page
Triangle hunt
Look around the house or classroom for triangle shapes, such as a sandwich cut diagonally or a roof end. Sketch them and mark where the base and height would go.
Squared paper designs
Draw a picture made only of triangles on squared paper. Write the base and height of each one and work out its area.
Rectangle and triangle pairs
Draw a rectangle, then draw a triangle that has the same base and height inside it. Write both areas side by side and talk about how they compare.
Who it is for
Parents
Sit beside your child for the first question, then let them lead. About 15 minutes is plenty. If they get stuck, ask them to draw the rectangle first. Praise careful thinking, not only correct answers.
Teachers
Use it as a starter after teaching the area of triangles, as a plenary, an early finisher task or a homework sheet. It needs no preparation beyond printing. Page 2 has support, stretch and answers for mixed ability groups.
Home educators
Print it as part of a wider maths plan and let your child explain each answer aloud. Squared paper and a ruler are all you need. The sheet is free to print again for brothers and sisters or for revision a few weeks later.
Where this fits
Before this, children learn to find the area of rectangles by multiplying length by width, and to count squares inside shapes. They also practise multiplication facts, which makes the calculation on this sheet quicker.
After this, children can move on to the area of parallelograms, which uses a similar idea of base and height. They can then work with compound shapes and meet volume. Knowing why a formula works helps with all of these.
Check it worked
Ask these when the sheet is finished. Listen for the reasoning, not just the answer.
- Why do you halve the answer?
- Which side is the height?
- How is a triangle like half a rectangle?
Questions parents and teachers ask
- What age is Area of Triangles for?
It is written for Year 6 (ages 10 to 11), in Key Stage 2. It suits children who can multiply confidently and have already met the area of rectangles.
- What will children practise?
They practise finding the area of a triangle from its base and height. They multiply the two measurements, halve the result and write the answer in square units.
- How long does it take?
It takes about 15 minutes. It is one player, so a child can work alone or with a grown up beside them. Short, focused sessions work better than long ones.
- What if it feels too hard?
Try drawing a rectangle with the same base and height on squared paper. Find its area, then halve it. Working through the first question together also helps.
- Do children need to draw the triangles?
No, but drawing can help. Squared paper lets children see the base and height and picture the rectangle around the triangle. Some children will prefer to calculate straight away.
- Is it free, and do I need colour printing?
Yes, it is free to print for home and classroom use. No colour is needed. It prints well in black and white on plain A4 paper.
- Can teachers and home educators use it?
Yes. Teachers can use it as a starter, plenary, early finisher task or homework. Home educators and tutors can use it alone or as part of a wider plan, and print it again for revision.
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Made by Jaques of London, making games for families since 1795. A printable supports classroom learning and does not replace a teacher.