Answer: The dimensions that will maximize area of the pen are 350 ft by 175 ft
Step-by-step explanation: The farmer has a total of 700 feet of fence for a rectangular pen which is in effect the perimeter. However, one side is by the river and would not need to be fenced. Hence we can determine that the perimeter would cover three sides only.
This means the sides would be in the ratio of 2 : 1 : 1
Hence, one side would be 2/4 and the other two sides would be 1/4 each
For the whole 700 meters of fencing, the sides can be calcualted as follows;
Length = 2/4 x 700
Length = 350
Width = 1/4 x 700
Width = 175
Therefore, with the length of fence available, the dimensions for the rectangular pen would be
Length = 350 ft
Width = 175 ft