Where on a map do you usually find the grid coordinate A1?

In the top left

Explanation:

On a map, the top has numbers or letters. Same goes for the left side. Since "A" and "1" are the first in the alphabet and while counting, it comes first. As you go out, the letter and number will change.

Example: A1, A2, B1, B2

answer is  

loa ≅ lma

to prove that the triangles are congruent using the aas congruence