▸Circumference is 31.4159 cm for a circle with radius 5.0000 cm.
- Radius is 5.0000 cm, diameter is 10.0000 cm, and the enclosed area is 78.5398 cm².
- The ratio of circumference to diameter is 3.14159, which is always equal to π (3.14159...) for any circle.
- A semicircle has a perimeter of πr + 2r = 25.7080 cm (the curved arc plus the straight diameter).
- Doubling the radius quadruples the area but only doubles the circumference - area grows with the square of r.
Next stepFor a sector or arc length, multiply the full circumference by the central angle in degrees divided by 360.