Question

A circular path of radius 20m situated in a Colony. Three boys Ankur, Syed and David sitting at equal distance on its boundary each having a toy telephone in has hand to talk each other. find the length of the string of each phone

(class 9 ,circles ,NCERT)

Answer 1

hey mate
here's the solution

Answer 2

Answer:

20 root 3

Step-by-step explanation:

Let the center of the circle be O

Given that, the three boys sits on equal distance at the circumference of the circle.

Thus, Let the three points be A, B and C

According to Question,

radius of the circle,

OA = OB = OC = 20 m

Join the points B and C

After that if we draw a perpendicular from O at BC at point D,

In triangle OBD,

Angle BDO = 90 degree

Angle BOD = 60 degree

Thus Angle OBD = 180 - ( 90 + 60 )

    Angle OBD = 30 degree

Therefore,

Cos 30  =  BD / BO

root 3 / 2 = BD / 20

BD = 10 root 3

So  length of BC = 2 BD

                            = 2 * 10 root 3

                           = 20 root 3

Thus the distance between each of the three boys is 20 root 3 m