Triangle Formulas
2D Shapes
Triangle
- Area
- A = ½ × b × h
- Perimeter
- P = a + b + c
- Angle sum
- ∠A + ∠B + ∠C = 180°
- b base
- h perpendicular height
- a, c other sides
Triangle formulas explained
The area of any triangle is half its base times its perpendicular height. Its perimeter is the sum of the three sides. Below are all the triangle formulas with what each letter means, a worked example and a free calculator.
- Area:
A = ½ × b × h - Perimeter:
P = a + b + c - Angle sum:
∠A + ∠B + ∠C = 180°
Triangle calculator
Live calculator
Triangle calculator
Worked example: area of a triangle
Given Base b = 10 cm, Height h = 6 cm, substitute the values into each triangle formula:
- A = ½ × 10 × 6 = 30 cm²
Triangle Formula SheetFormulas, variables, a worked example and practice questions with answers.Download PDFOpen
Triangle formulas FAQ
What is the formula for the area of a triangle?
The area of a triangle is A = ½ × b × h, where b is the base, h is the perpendicular height.
What is the formula for the perimeter of a triangle?
The perimeter of a triangle is P = a + b + c, where b is the base, a, c are the other sides.
What is the formula for the angle sum of a triangle?
The angle sum of a triangle is ∠A + ∠B + ∠C = 180°.
Can I download the triangle formulas as a PDF?
Yes. Use the Download PDF button on this page for a free printable triangle formula sheet with a worked example and practice questions.
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