Question

AB and CD are two common tangents to circles which touch each other at C. if D lies on AB such that CD = 4cm , then AB =

a) 4 cm b) 6 cm c) 8 cm d) 12 cm

Answer 1

also CD=AD=4cm   ......(1) (tangents drawn from an exterior point are equal)
CD=BD=4cm         .........(2) (tangents drawn from an exterior point are equal)
Then , AB=AD+BD =4+4 {from (1) and (2)}
=> AB=8cm  Option (c) is correct answer

Answer 2

AB = 8 cm.      

Step-by-step explanation:

Given:

As shown in the figure, AB and CD are two common tangents to circles which touch each other at C.

CD = AD = 4 cm   (tangents drawn from an exterior point are equal)

CD = BD = 4 cm   (tangents drawn from an exterior point are equal)

Now AB = AD + BD =4 + 4 = 8 cm.

Option (c) is right answer.