The Brainliest Answer!
First, notice that 15,20,25 is produced by the primitive pythagorean triple (3,4,5), so it is a right triangle and the area is obtained by simply multiplying the legs and dividing by 2 :
Area = \frac{15*20}{2}=150

Another way to obtain the same area is by considering 25 as base, then the height is half of the common chord; call the height, l/2 :
Area = \frac{25*l/2}{2}=\frac{25l}{4}

Set both areas equal to each other and solve the length of common chord, l :
2 4 2
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!