Answer:
The answer would be 8.1
Explanation:
For the smaller triangle, you use the pythagorean theorem. a squared + b squared = c squared.
To find one of the legs, you do 5 squared - 3 squared = b squared.
25 - 9 = b squared. (BD)
16 = b squared
4 = b
Now for the bigger right triangle. You still use the same tactic.
7 squared + 4 squared = c squared (which is AB)
49 + 16 = c squared
65 = c squared
That means c would equal: square root of 65, which is 8.0622577483 which rounds to 8.1