Final answer:
To find the lengths of ab and check the answer using a different method, we need more information about what ab represents in the context of the problem.
Step-by-step explanation:
To find the lengths of ab and check the answer using a different method, we need more information about what ab represents in the context of the problem. The provided solution and steps are related to measuring lengths and vectors, but they do not specifically provide a method for finding the length of ab. Please provide additional context or details for a more specific answer.