Since this a right triangle and we have the side measurements of the hypotenuse and a side we can use the Pythagorean theorem to find the measurement of the other side
Let the missing side, m, equal b
c^2=a^2+b^2
12^2=10^2+b^2
10^2+b^2=12^2
10^2+b^2-10^2=12^2-10^2
b^2=44
b=√44, b=-√44
Angle measurements cannot be negative, therefore side m = √44 = 6.6 units
