The circumference of a circle with a radius of 5cm is: 31.42 cm
The perimeter of a quarter circle is 2 radii plus a quarter of the circumference of the whole circle: → 2 × radius + ¼ × 2 × π × radius = 32.13 cm → radius × (2 + π/2) = 32.13 cm → radius = 32.13 ÷ (2 + π/2) cm ≈ 9.00 cm
A circle with a radius of 40 cm has an area of 5,026.55 square cm.
The radius is 5.00 cm.
The radius measures from the center of the circle to the perimeter (outside), so if the radius is 8.5 cm that would make the diameter of the circle 17 cm. (8.5 cm X 2 = 17 cm)
Pi= 3.1416 circle / 3.1416=diameter
The side of the square is equal to the diameter of the circle, in this case 2a so the perimeter is 8a cm.
The perimeter is pi*r + 2r = 92.6 cm
If it is a 7.1 cm radius circle, then its radius is exactly 7.1 cm!
The radius of the circle is: 9.549 cm
The radius of a 2 cm circle is: 1 cm
If a circle has a circumference of 16 cm then the radius is about: 2.546 cm