Hey,here is the Answer to ur question....
Given: Angel BAC=BOA=90 degrees
BO= 9
OC=7
AO=y
To find: value of y
Solution: In triangle BAC and triangle BOA ,we have,
Angle BAC=angel AOB
Angle B= Angle B (Angle B common in both triangles).
=>triangle BAC similar to triangle BOA ( A.A criterion rule )
=>BA/BO=AC/OA=BC/BA
=>BA/BO=BC/BA
=>(BA)^2=BC*BO
=>(BA)^2=16*9
=>(BA)^2=144
=>BA= root of 144
=>BA=12
So by Pythagoras theorem;
(AB)^2=(BO)^2+(AO)^2
(12)^2=(9)^2+(y)^2
144=81+y^2
144-81=y^2
63=y^2
3root7=y
Hope this helps you......