Answer:
6
Step-by-step explanation:
This is an example of a Pythagorean triple. Any triangle sides in the ratio of
3:4:5 (there are many ratios but this is the one used in the problem) is a right triangle.
If we divide 2 from 8 and 10, we get 4 and 5, so we know the last side must be 3.
Undo the division to get 3*2=6