Question

. Two circles are of radii 7 cm
and 2 cm their centres being
13cm apart. Then the length
of direct common tangent to
the circles between the points
of contact is​

Answer 1

Answer:

Correct option is

A

11.18cm

Radius of first circle AB=8cm

Radius of first circle DC=3cm

Length of common direct tangent BC=10cm

We need to find the distance between their centers means AD.

⇒ Length of direct tangent =

(AD)

2

−(AB−DC)

2

⇒ 10=

(AD)

2

−(8−3)

2

⇒ 10=

(AD)

2

−(5)

2

⇒ 100=(AD)

2

−25

⇒ 100+25=(AD)

2

⇒ (AD)

2

=125

⇒ AD=5

5

cm

∴ AD=11.18cm

Hence, the distance between two centers of a circle is 11.18cm.

Answer 2

Answer:

answer of your question is 11.22