Yes, because bigger side i.e 12 cm can be hypotenuse
and sides 6 cm and 4 cm become base and perpendicular.
H² = P²+B². 
yes this is right angle triangle
How do u know
by the Pythagoras formula
No ... you ppl are wrong. A triangle canot be formed with these measurements. Check my answer
Yes exactly u r right mathexpert I also thought the same
The Brainliest Answer!
We know that, 
The sum of the lengths of any two sides of a triangle is more than the third side.

4 + 6 is not more than 12

therefore, a triangle cannot be formed with these measurements
2 5 2