Answer:
8√2
Explanation:
Notice that this is a 45-45-90 triangle (isosceles right triangle). This type of triangle has a property where the ratio between side lengths is x : x : x√2, where x√2 is the measure of the two equal legs and is the measure of the hypotenuse.
Since we know the measure of one of the smaller legs is 8, then we can set x in the ratio to 8 --> 8 : 8 : 8√2
Thus, the length of BC (hypotenuse) is 8√2