Equilateral triangle
Area and perimeter, with the formula worked through and a drawing to scale.
Result
- Area
- 15.5885 sq ft
- = 15.5885 sq ft · 1.4482 m²
- Perimeter
- 18 ft
- = 18 ft · 5.4864 m
- Height
- 5.1962 ft
The working
Area: A = (√3 ÷ 4) × a²
Perimeter: P = 3a
A = (√3 ÷ 4) × 6² = 15.5885 P = 3 × 6 = 18
Values in feet; areas in sq ft.
About the equilateral triangle
Three equal sides and three 60° corners. Its height is a × √3 ÷ 2, about 0.866 of a side.
Every formula on this site is explained step by step in Learn: area and perimeter.
Other shapes
Square Rectangle Parallelogram Rhombus Trapezoid (trapezium) Kite Triangle — three sides Triangle — base and height Right triangle Isosceles triangle Triangle — two sides and the angle between Circle Semicircle Quarter circle Sector (pie slice) Circular segment (arch) Ring (annulus) Ellipse (oval) Regular polygon (pentagon, hexagon, octagon…) L-shape Any polygon — by corner points