Instruction

1

The diameter

**of a circle**is a line segment that passes through the center**of the circle**and connects two most distant between a point lying on**the circumference**. The length of this segment is also called a diameter**of the circle**. The radius is half the diameter**of a circle**, so if you know the diameter of this**circle**to find its**radius**by dividing it in half. R = D/2 where D is the diameter**of the circle**.2

The length of the curve, forming a circle on a plane is the length of the

**circumference**. If the known length**of a circle**you can use the formula: R = L/2?, where L is the length**of the circle**, ? is a constant equal 3,14159... Constant ? equal to the ratio of the length of**the circumference**to the diameter, this value is the same for all circles.3

A circle is a geometric figure that represents the portion of the plane bounded curve is a circle. If you know the area of a circle, find

**the radius****of a circle**from the following formula: R = v(S/?), where v is the square root, S – the area of a circle.Note

The radius of the circle is the positive value not equal to zero.