2. Circumference
The circle is the locus of points on a plan that are at
the same distance r from a fixed point called the center
of the circle.
3. Radius
Radius of a circle is a straight line with one end in the
center of the circle and the other end at any point on
the circumference. In the figure, the line segments
OA, OB, OD are radius.
O
4. Diameter
Diameter of a circle is a chord passing through the
center of the circle. We observe that the diameter is
the largest chord of the circle.
In the figure, the segment BD is a diameter.
5. Chord
It is a line segment whose endpoints belong to the
circle.
In the figure the line segment BC is a rope.
6. QUESTIONS
1 - The radius is 3.5 cm. What is the diameter?
2 - If the diameter is 8.2 cm, what is the radius?
7. Solutions
1 - The radius is 3.5 cm. What is the diameter? 7,0 cm
2 - If the diameter is 8.2 cm, what is the radius? 4,1 cm
