How to Calculate Isosceles Triangle
What is Isosceles Triangle?
An isosceles triangle has two equal sides (legs) and two equal base angles. The axis of symmetry runs from the apex (the unique vertex) to the midpoint of the base. Many real-world structures use isosceles triangles for their symmetry and stability.
Formula
- h
- (c/4) × √(4a² − c²) — (c/4) × √(4a² − c²)
Step-by-Step Guide
- 1Two sides equal: a = b (legs), c = base
- 2Base angles equal: α = β
- 3Apex angle γ = 180° − 2α
- 4Height h = √(a² − (c/2)²)
- 5Area = (c/2) × h = (c/4) × √(4a² − c²)
Worked Examples
Frequently Asked Questions
What is Isosceles Triangle?
An isosceles triangle has two equal sides (legs) and two equal base angles. The axis of symmetry runs from the apex (the unique vertex) to the midpoint of the base
How accurate is the Isosceles Triangle calculator?
The calculator uses the standard published formula for isosceles triangle. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Isosceles Triangle calculator use?
This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Isosceles Triangle calculator use?
The core formula is: Two sides equal: a = b (legs), c = base. Each step in the calculation is shown so you can verify the result manually.