Equilateral Triangle Calculator
Compute all properties of an equilateral triangle from one side length.
Inputs
units
Area
43.3013sq units
Perimeter
30.0000units
Height
8.6603units
Inradius
2.8868units
Circumradius
5.7735units
Step by step
Area
A = (√3/4) × 10²
= 43.3013
Height
h = (√3/2) × 10
= 8.6603
Perimeter
P = 3 × 10
= 30
How it works
All sides and angles of an equilateral triangle are equal (60° each). Its area, height, inradius and circumradius are all derived from the single side length.
Formulas
Area
A = (√3/4) × s²
- s
- Side length
Height
h = (√3/2) × s
- s
- Side length
Frequently Asked Questions
Are all equilateral triangles similar?
Yes — all equilateral triangles are similar because they all have three 60° angles. They differ only in scale.
What is the relationship between inradius and circumradius?
For an equilateral triangle, the circumradius is exactly twice the inradius: R = 2r.