EXPLANATION
Let's see the facts:
The height of the triangle bisects it, so this is an Isosceles one.
The Area is 6.12 square feet.
By Isosceles Triangle Definition,
Isolating the base:
Multiplying both sides by 2:
Dividing both sides by the height:
Switching sides:
Replacing terms:
Answer: the length of the base is 3.6 feet.