Question

The distance of a point p from the centre of the circle is 20 cm. The radius of the circle is 5cm. A line through p is tangent to the circle at
b. Find the length of pb

Answer 1

Length of pb is 4 cm

Step-by-step explanation:

Let,

The center of Circle is o

A radius always perpendicular on its tangent

SO, triangle opb is right angled at b

On applying Pythagoras:

(Hypotenuse)^2 = (Perpendicular)^2 x (Base)^2

(op)^2 = (ob)^2 x (pb)^2

(20)^2 = (5)^2 x (pb)^2

(pb)^2 = 20 x 20 / 5 x 5

(pb)^2 = 4 x 4

(pb)^2 = 16

(pb) = 4 cm

So, Length of pb is 4 cm

Know More:

Q.1. Line which is a tangent is parallel to other tangent

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Q.2. Define Secant and Tangent ?

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Answer 2

Answer:

by Pythagoras theorem

b²*p²=h²

x²+5²=20²

x² =20²/5²

x² =4*4

x² =16

x=4