Question

(2 marks each)
For two concentric circle of radius 25 cms and 7 cms, the chord of the oft
larger circle touches the smaller circle. Find its longth,​

Answer 1

given,

Two concentric circles with radii 7cm and 25cm .

to find,

the length of the cord of the larger circle which touches the smaller circle.

on applying Pythagoras theorem in triangle AOC

(AO) ^2 = (AC) ^2+(OC) ^2

(25) ^2 = (AC) ^2+(7) ^2

625 = (AC) ^2+49

(AC) ^2 = 625-49

AC = √576

AC = 24

Similarly, if we apply Pythagoras theorem in triangle OCB,

we get CB=24cm

therefore, AB = AC+CB

AB = 24+24

AB = 48cm

hence, the length of the cord of the larger circle which touches the smaller circle is 48cm