B should be the correct answer
Answer:
13
Step-by-step explanation:
First drop the line.
How many units is it from Point r to the x axis?
12.
How many units is it from Point r to the y axis?
5.
Now we can use the Pythagorean Theorem.

X is equal to 12
This is because 5 was multiplied and 6 making 30. So you have to multiply 2 and 6 making x 12. Hope that makes sense