consider the two points given on the graph. What do they mean in terms of the situation? Explain your reasoning

Can someone answer these problems for me

Find the value of the cosine for angle a

Problem melissa is her dad build a walkway in their backyard. the walkway will be 54 feet long and 1.5 feet wide. the local hardware store sells tiles which are 1.5 by 1.5 feet and come in boxes of 12. how many boxes of tiles do they need?