Hey mate,.

Let abc be a right angled triangle with

/_B,then it's hypotenuse AC=25cm

Let base BC = x cm ,then

perimeter of /_ abc =AB+BC+CA

=> 60 cm = AB + x cm+25cm =>AB=(35-x cm)

In ∆ABC, /_ B =90°

AB^2+BC ^2= AC^2(Pythagoras theorem)

=>(35-x)^2+x^2=26^2

=>1225-70x+ x^2+x^2=625

=>2x^2-70x+1225-625=0

=>2x^2-70x+600=0

=>2x(x-20)-30(x-20)=0

=>(x-20)(2x-30)=0

=>x-20=0

x= 20

Hope it will help you