Answer: BC = 5.83
Explanation:
Luckily, the triangle is placed on the graph nicely so we can count the legs of the triangle:
AB = 5
AC = 3
BC = ?
To find BC, we can simply use the Pythagorean Theorem:

5^2 + 3^2 = c^2
25 + 9 = c^2
34 = c^2
Now square root to find c, or BC.

c = 5.83 (rounded by nearest hundredth)