Radius of a circle= Perimeter of the circle/2*pi Radius is half the diameter Radius is the length of a straight line from the center point of the circle to the edge of the circle.
If it is a 7.1 cm radius circle, then its radius is exactly 7.1 cm!
If the circumference of a circle is 132cm its radius is: 21.01 cm
The diameter of a circle is twice the radius. A circle with a radius of 9 would have a diameter of 18. (9*2=18).
the circumfrence of a circle is pi times it's radius squared.
A = 1,257 cm2
Radius = Diameter/2 = 10 cm
WOW really? It would be 20cm
1256 cm2
A circle with a radius of 10 cm has an area of 314.16 square cm
The Diameter is the distance from one side of the circle all the way to the other side. The Radius is half the distance in a circle. Simply put: 40cm = Diameter 20cm = Radius (Half the distance) :)
When the angle is measured in radians arc_length = angle x radius. So, 20cm = angle x 12cm => angle = 20cm / 12cm ~= 1.67 radians
The formula for the circumference of a circle is C = 2πr, where C is circumference, π is pi (approx. 3.142), and r is the radius. So, for a circle with a radius of 6cm, C = 2(3.142)(6cm) = 18.852cm Rounding to the proper number of significant figures, this answer would be 20cm.
The surface are of a cylinder whose radius is 10cm and height is 20cm is 1884.96cm2
This cannot be properly answered because a 20 cm radius equates to a 40 cm diameter. Also, a 50 cm diameter means a 25 cm radius.
Normally, the amount of the side of the rectangle below the quarter circle on it would expected to be calculated. However, the radius of the circle equals the amount that is subtracted, but in calculating the perimeter it has to be added back in again as it forms part of the perimeter. Thus the perimeter is the perimeter of the rectangle plus a quarter of the circumference of the circle. → perimeter = 2 × (20cm + 2 cm) + ¼ × 2 × π × 11 cm ≈ 44 cm + 3.14 × 11/2 = 61.27 cm.
Make a sketch of the situation. From a corner of the equilateral triangle draw a radius of the large circle, and from an adjacent side draw a radius of the smaller circle. You should have formed a small right-angled triangle with a known side of 10cm. and known angles of 30o, 60o and 90o. (The interior angles of an equilateral triangle are each 60o.) The hypotenuse is the unknown radius of the larger circle. But since cos 60 = 0.5, it is evident that the hypotenuse is 20cm. long.