I need help im in the test right now

Answer:
B. 10.2 cm
Explanation:
Because the figure is a rectangle, all angles are right angles which means that the pythangorean theorem can be used.
a² + b² = c².
Since side c is JL measuring at 13 cm and side a is JM measuring at 8 cm.
We can rearrange the formula to solve for b.
a² + b² = c²
–a² –a²
b² = c² – a²
√b² = √(c² – a²)
b = √(c² – a²).
b = √((13)² – (8)²)
b = √(169 – 64)
b = √(105)
b = √105 = 10.24695076595... ≈ 10.2 cm