The procedure followed in the above case may be followed as it is, and when the child
is allowed to measure the lengths of the strips, he/she will understand that the
tangents drawn from a point outside a circle are of equal length.
- Chord
A chord of a circle is a line segment whose end points lie on the circle. The diameter
is also a chord. If the chord passes through the center of the circle then it is called
as the diameter. Note that the diameter is the longest chord of the circle.
The idea of chord may be taught with the aid of a circular ring and a suitable wooden
strip. Embossed diagrams may also be used to enable the child to understand the
idea better. Paper folding is also useful.
- Secant
A line which intersects the circle in two points is called the secant of the circle. The
procedure followed in teaching the idea of chord may be followed to teach the idea of
secant also.
- The value of ‘π’
The symbol π is used to find out the area and the circumference of a circle.
Approximately the value of π is equivalent to^227 or 3.1416...
The idea is to be explained orally, supported by the explanation regarding the usage
of the value of π in finding the circumference and area of a circle.
- Circumference of a circle
The length of the outer boundary of a circle is called its circumference. The circumference
of a circle can be found using the formula 2 π r, where ‘r’ is the radius of the circle.
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