Page 211 - New Medley 4 Semester 1

Circumference
Circumference: The boundary of a circle is called its
circumference.

Relationship Between the Radius and the Diameter

In the given figure, OA or OB is the radius and AB is the diameter.

So, AB = OA + OB = OA + OA

= 2OA ( OA = OB) Radius Radius
A O B
Thus, the length of AB is double of OA or OB. Diameter

That means, Diameter = 2 × Radius

Diameter
or Radius =
2

EXERCISE 6.3

A. Fill in the blanks.

1. If the radius of a circle is 8 cm, then the diameter is .

2. If the diameter of a circle is 20 cm, then the radius is .

B. Write the names of the following in the given circle.

1. PQ is .
2. O is .
N

3. OR is . M
L
4. LM is . O

� P Q
5. LNM is .

6. is the diameter.
R
C. Complete the table.

Radii 3 cm 7 cm 1 m 20 cm

Diameters 8 cm 18 cm 42 cm

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