Question

two concentric circles are the radii 13cm and 15cm , the length of the chord of a larger circle which touches the smaller circle is ​

Answer 1

Answer:

Let C

1

,C

2

be two circles of radius 13,12 respectively.

Let r

1

=13 cm and r

2

=12 cm

Draw a chord AB tangent to C

2

at point P.

Join O−A and O−B

OP=12 cm ....... (Radius of smaller circle)

OA=OB=13 cm ....... (Radius of bigger circle)

AB is tangent to C

2

and OP perpendicular AB

∴ ∠OPA=∠OPB=90

o

Using Pythagoras theorem,

OA

2

=OP

2

+AP

2

⟹AP

2

=OA

2

−OP

2

⟹AP

2

=13

2

−12

2

=169−144=25

∴AP=5 cm

Similarly, PB=5 cm

∴ AB=AP+PB=5+5=10 cm

Hence, the answer is 10.

Answer 2

Answer:

15cm is the answer

Step-by-step explanation:

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