Isosceles Triangle Calculator
Isosceles Triangle Calculator
An isosceles triangle is a triangle that has two equal sides and two equal angles. Using the isosceles triangle calculator, you can quickly find the triangle's height, area, perimeter, vertex angle, and base angles.
Simply enter the base and equal side or the base and height to calculate all other properties instantly.
Diagram of an isosceles triangle with equal sides (a), base (b), and height (h).
Height Formula
h = √(a² − (b/2)²)
Where a is the equal side and b is the base.
Area Formula
Area = (b × h) / 2
Multiply the base by the height and divide by two.
Perimeter Formula
P = 2a + b
Add both equal sides and the base.
Example Calculation
Suppose an isosceles triangle has:
- Base b = 6 units
- Equal side a = 5 units
Step 1: Calculate Height
h = √(a² − (b/2)²)
h = √(5² − (6/2)²)
h = √(25 − 9)
h = 4 units
Step 2: Calculate Area
Area = (b × h) / 2
Area = (6 × 4) / 2
Area = 12 square units
Step 3: Calculate Perimeter
P = 2a + b
P = 2(5) + 6
Perimeter = 16 units
| Property | Value |
|---|---|
| Height | 4 |
| Area | 12 |
| Perimeter | 16 |
FAQ on Calculator
An isosceles triangle is a triangle that has two equal sides and two equal angles.
Use the formula h = √(a² − (b/2)²) where a is the equal side and b is the base.
The area is calculated using Area = (base × height) / 2.