Triangle Area Calculator (9 diferent ways)
This free online calculator will help you to find the area of a triangle (9 different ways).
Using this online calculator, you will receive a detailed step-by-step solution to your problem, which will help you understand the algorithm how to find triangle area.
Calculation of Triangle Area
Select method (defined data):
Input data:
a =
b =
c =
c =
Area in
Entering data into the triangle area calculator
To calculate the area of a triangle:
- select defined datas;
- enter the value of datas;
- select units of measurement - meter (m), centimeter (cm) or millimeter (mm);
- select in which units you want to get the area - square meters (m2), square centimeters (cm2) or square millimeters (mm2).
You can input only integer numbers or fractions in this online calculator. More in-depth information read at these rules.
If you have any difficulties with units conversion, you can use the length converter and area converter.
Additional features of triangle area calculator
- Use and keys on keyboard to move between field in calculator.
You can find the area of a triangle if you know the following values:
- Lengths of the three sides (using Heron's formula)
- Lengths of the two sides and angle between them
- Lengths of the base of the triangle, and altitude of the triangle
- Lengths of the three sides and circumradius
- Lengths of the three sides and in-radius
- Lengths of the semiperimeter and in-radius
- Lengths of the two sides of triangle and angle
- Length of the side of triangle and two angles
- Length of the circumradius and two angles
Theory. Triangle Area
The formulas for calculating the area of a triangle
- Area of a triangle when we know the base and the height
The area of a triangle is equal to half of base times height.
A =
1 2 - Area of a triangle when we know the lengths of all three of its sides
Heron's formula
A = √s(s - a)(s - b)(s - c)
- Area of a triangle when we know two sides and the included angle
The area of a triangle is equal to half of a product of two sides and sine of the angle between this sides.
A =
1 2 - Area of a triangle when we know three sides and circumradius
A =
a · b · с 4R - Area of a triangle when we know semiperimeter and in-radius
The area of a triangle is equal to semiperimeter times in-radius.
A = s · r
where A - the area of a triangle,
a, b, c - the length of sides BC,AC,AB accordingly,
h - the height, the length of the altitude,
γ - the angle between sides a and b,
r - the length of the in-radius,
R - the length of the circumradius,
s - the semiperimeter, or half of the triangle's perimeter.
You can input only integer numbers, decimals or fractions in this online calculator (-2.4, 5/7, ...). More in-depth information read at these rules.
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See also
Triangle. Formulas, characterizations and properties of triangle
Area Formulas for Geometric Figures.
Length and width converter
Area converter
Perimeter calculators
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