The coordinates of the fourth vertex are (0,0). I hope this helps!
Answer:
6.3
Step-by-step explanation:
First off, we need the distance formula, which is:
If we plug in the points, we get:
If we simplify everything under the square root, we get:
In decimal, the answer is 6.3
If ABC type question, then sometimes. If its extended, then only when the lines coincide with each other or if one of the lines aren't linear.