How many feet of fencing are need to enclose a triangular lot?

There is no specific measurement given in this problem. However, you simply solve for the perimeter of the triangle to know the number of feet of fencing that is needed. 

Perimeter is simply adding up all the sides of the triangle. In the event that the area of the triangle is given, simply solve for its side measures using the formula of the area of a triangle.

Area of a  right triangle = ab/2 
where a and b are the short and long legs of the right triangle and you can solve for the hypotenuse using the Pythagorean theorem.  

Area of an equilateral triangle = √3/4 * a²
where a is the measure of the side. equilateral means that all three sides are equal in measure.

Area of a triangle = hb/2
where h is the height; b is the base.