Circle
Area and perimeter, with the formula worked through and a drawing to scale.
Result
- Area
- 78.5398 sq ft
- = 78.5398 sq ft · 7.2966 m²
- Circumference
- 31.4159 ft
- = 31.4159 ft · 9.5756 m
- Diameter
- 10 ft
The working
Area: A = π r²
Perimeter: C = 2 π r
A = π × 5² = 78.5398 C = 2 × π × 5 = 31.4159
Values in feet; areas in sq ft.
About the circle
π is about 3.14159. Measure across the middle for the diameter and halve it for the radius — a round table 48″ across has a 24″ radius.
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 Equilateral triangle Triangle — two sides and the angle between 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