Multiply the radius by (2 x pi).
radius = diameter/2 circumference = 2*pi*radius or pi*diameter area = pi*radius2
That depends on what you mean by a "20 ft semicircle".A semi-circle is a half circle.A 20 ft circle could be:A circle of diameter 20 ftThe perimeter of the semicircle is half the circumference plus the diameter → perimeter = 1/2π 20 ft + 20 ft= 10π + 20 ft≈ 51.42 ftA circle of radius 20 ftThe perimeter of the semicircle is half the circumference plus double the radius → perimeter = 1/2 2π 20 ft + 2 x 20 ft= 20π + 40 ft≈ 102.08 ftA circle of circumference 20 ftThe perimeter of the semicircle is half the circumference plus the diameter → perimeter = 1/2 20 ft + 20 ft ÷ π= 10 ft + 20/π ft≈ 16.37 ftHowever, if a 20 ft circle is a circle with a circumference (= perimeter) of 20 ft then a 20 ft semi-circle could be a semicircle with a perimeter of 20 ft→ perimeter = 20 ft
That depends what you mean with "a 20 cm. circle". If 20 cm. is the radius, you already have the answer. If 20 cm. is the diameter, the radius is half the diameter. (10cm)
If the circumference of a circle is 62.8 inches the diameter is: 20 inches.
The diameter of a 20 foot circumference circle is about 6.366 feet. (C / Pi = diameter).
The radius of a circle whose circumference is 40pi is 20 units.
The radius of this circle is 10 units.
Circumference of a circle equals Pi times the double the radius C = 2 x 3.14 x radius C= 2 x 3.14 x 20 C = 125.6 The circumference of a circle with a 20 foot radius is 125.6 feet.
20
20; the diameter of a circle is twice its radius.
radius = 20/(2*pi) = 3.183098862 inches
Circumference = Pi * diameter. so Circumference = pi * 20 = 62.832
The diameter is 20. (The diameter is twice the radius. The radius is from the center to any edge of the circle.)The circumference is 62.83. ( The diameter X Pi (3.14... equals the circumference.)OR:Using only the radius: (2 X Pi X radius will also equal the circumference.)In this example 2 X 3.14 X 10 (2 X 3.14 = 6.28 X 10= 62.8)
Circumference = 2*pi*r = 125.66 metres
Divide the circumference by (2 x pi).
r = 3.18 inches.
It is 3.18 feet, approx.