"A relation between two sets is a collection of ordered pairs containing one object from each set. If the object x is from the first set and the object y is from the second set, then the objects are said to be related if the ordered pair (x,y) is in the relation. A function is a type of relation."
The area of the triangle is a=( m x n) /2 in cm² , implies 2xa = m xn the area of the rectanglle A= n x m in cm² but we know <span> 2xa = m xn = A, </span> that means the surface of the rectangle is 2 times of the area of the triangle
