# Two circles of radius 15 cm and 20 cm respectively have the distance between their centres as 25. what is the length of the common chord ?

1
by namku

2015-05-01T17:24:32+05:30
First, notice that is produced by the primitive pythagorean triple , so it is a right triangle and the area is obtained by simply multiplying the legs and dividing by 2 :
Area =

Another way to obtain the same area is by considering as base, then the height is half of the common chord; call the height, :
Area =

Set both areas equal to each other and solve the length of common chord, :

450 = 50x
oh my gosh i was writing 225x2 as 500 :( sorry for wasting ur time
Haha np :) i like ur method more than mine
urs is shorter more preferrable thanks alot!
np:)