Question

Construct a tangent to a circle of radius 4cm from a point on the concentric circle of radius 6cm and measure its length. Also verify the measu

rement by actual calculation.

Answer 1

Answer:

(1)Draw two concentric circle C

1

and C

2

with common center

0 and radius 4cm and 6cm

(2) Take a point P on the outer circle C

2

and join OP.

(3) Draw the bisector of OP which bisect OP at M'.

(4) Taking M' as center and OM' as radius draw a dotted circle which

cut the inner circle C

1

at two point M and P.

(5) Join PM and PP'. Thus, PM and PP' are required tangent.

On measuring PM and PP'.

PM=PP

′

=4.4cm

Bycalculation:

InΔOMP,∠PMO=90

0

PM

2

=OP

2

−OM

2

(bypythagorastheorem)

PM

2

=(6)

2

−(4)

2

=36−16=20

PM

2

=20cm

PM=

20

=4.4cm

Hence,

thelengthofthetangentis4.4cm