Lacy has $600 set aside to build a rectangular exercise kennel for her dogs. She will buy fencing material for $15/ft. Because the side of an existing barn will be used for one of the sides of the kennel, only three sides need to be fenced.

Question

Lacy has $600 set aside to build a rectangular exercise kennel for her dogs. She will buy fencing material for $15/ft. Because the side of an existing barn will be used for one of the sides of the kennel, only three sides need to be fenced. 
A.) Determine the dimensions of the kennel that will enclose the maximum area. 
B.) What area will be enclosed? 
If someone could please help me step by step with this question that would be awesome. TIA

Ms. Sue · Answer

A square will enclose the maximum area. She has enough money for 40 feet of fencing. I suggest dimensions of 14 by 13.