Question

the length of a tangent from a point A at distance 5cm from the centre of the circle is 4cm. the radius of the circle is
a)2cm
b)3cm
c)4cm
d)5cm​

Answer 1

Answer: b)3cm is the correct answer.

Step-by-step explanation: Let AT be the tangent drawn from a point A to a circle with centre

O and OA=5 cm and AT=4 cm. Since tangent at a point is

perpendicular to the radius through the point of contact

∴OT⊥AT

∴ from right angled △OAT,

(OA)

2

=(OT)

2

+(TA)

2

⇒(5)

2

=(OT)

2

+(4)

2

⇒25−16=(OT)

2

⇒9=(OT)

2

⇒OT=3 cm

∴ radius of the circle =3 cm.

Answer 2

Answer:

3 cm is the right answer.

Step-by-step explanation:

By using phythagorus theorem

25 - 16 = 9

Radius of the circle is 3 cm.