Atriangle has two sides that measure 12 meters and 3 meters. which could be the measure of the third side?

If we use pythagoras..

c=12
a=3

c^2=a^2 + b^2
12^2=3^2 + b^2
144=9 + b^2
135= b^2
b= 11.61

The other side measures 11.61