Area of a Triangle Worksheet Generator
Build a printable area-of-a-triangle worksheet with an answer key. Choose the base and height ranges, generate a fresh set of problems, and let the student page grade the answers.
Make a triangle-area worksheet → Free · runs in your browser · answer key includedThe formula
A = ½ × base × height
A triangle covers exactly half of the rectangle that would box it in, and that is where the one-half comes from. Multiply the base by the height, then take half. The height is the straight-up distance from the base to the opposite corner, measured at a right angle — not the length of a slanted side.
A worked example
A triangle has a base of 10 cm and a height of 6 cm. Find its area.
Multiply base by height: 10 × 6 = 60.
Take half: 60 ÷ 2 = 30.
Area = 30 cm²
Two mistakes come up often. The first is forgetting to halve, which doubles the answer. The second is using a slanted edge as the height instead of the perpendicular distance to the base. When the height is drawn inside the triangle, it always meets the base at a right angle.
Sample problems
- A triangle has a base of 12 cm and a height of 5 cm. Find its area. (30 cm²)
- A triangular sail has a base of 7 m and a height of 4 m. Find its area. (14 m²)
- A triangle has a base of 9 cm and a height of 8 cm. Find its area. (36 cm²)
- A triangular flag has a base of 20 cm and a height of 15 cm. Find its area. (150 cm²)
In the tool you set the ranges the base and height are drawn from, so every worksheet is a different set.
Who it's for
Area of a triangle usually follows the rectangle, landing around grades 5 to 8. It suits classroom practice, homework, and homeschool review, and it is a natural next step once students can find the area of a rectangle.
How to make one
- Open Formula Worksheet Maker.
- Drag the Area of a Triangle formula onto the sheet.
- Set the range for base and height.
- Generate the student page, the questions PDF, and the answer key.
- Print it, or save as a PDF and reuse it. Regenerate for a fresh set anytime.
Questions people ask
- Does the worksheet come with an answer key?
- Yes. Each sheet has a matching key, and the student page checks every answer against it.
- Can I set how hard the numbers are?
- Yes. You choose the base and height ranges, so the problems can be gentle or more demanding.
- Does it explain the one-half step?
- The answer key shows the final value for each problem, so students can compare their own working against the correct result.
- Is it free to print?
- Yes. The tool is free, runs in your browser, and needs no account. Print or save each worksheet as a PDF.
Ready to make your worksheet?
Set your base and height ranges and generate an area-of-a-triangle worksheet with its answer key.
Open Formula Worksheet Maker →