Question

the length of the cord which is at a distance of 12cm from the center of a circle of radius 13cm is ?

Answer 1

√169-144=√25=5. 5*2=10 is the required length of the cord.

Answer 2

p be the mid point of ab 
 ap=pb 
op=12cm
ao=13cm 
by pythagorus theorem 
ao2=op2 +ap2
ap2 =13 2 - 12 2 
       = 169-144
       =  25 

ap   = 5cm
ab =ap+bp
     = 5+5
     = 10cm