Geometry | Term 1 Chapter 1 | 4th Maths - Identifying center, radius and diameter of a circle | 4th Maths : Term 1 Unit 1 : Geometry
Chapter: 4th Maths : Term 1 Unit 1 : Geometry
Identifying center, radius and diameter of a circle
Identifying
center, radius and diameter of a circle
Circle is perfectly round in
shape. It has no sides and no diagonals.
'O' is the center of the circle. The distance from the center to
each of these points A, B, C, D, E is the radius of the circle.
Radius is equal in length
(OA=OB=OC=OD=OE).
All the radii are equal in length
in a circle.
A Line segment AB passes through
the center of the circle O. AB is the diameter of the circle. The line segments
XY and LM are the Chords (XY, LM, AB).
The longest chord of a circle is
the diameter (AB). The radius is
always half of the diameter.
Diameter is the longest chord.
EXAMPLE
1. Find the diameter of a circle
whose radius is 5 cm.
Diameter = 2 x radius
= 2 x 5
Diameter = 10 cm
Diameter = 2 × radius
Radius = Diameter / 2
2. Find the radius of a circle
whose diameter is 88cm.
Radius = diameter / 2 = 88 / 2
Radius = 44 cm
Activity
Measure the radius and diameter
of the following circles.
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