Answer:
BC = 2
Step-by-step explanation:
We first need to use triangle BAD to find BD,
BD is the hypotenuse, so use pythagorean theorem...
(√23)² + (√13)² = (BD)²
23 + 13 = (BD)²
36 = (BD)²
6 = BD
Now BD is the hypotenuse of triangle BCD, so use pythagorean theorem agian to find BC
(4√2)² + (BC)² = 6²
32 + (BC)² = 36
(BC)² = 4
BC = 2
