
If a/b = c/d, then a, b, c, and d are called the first, second, third, and fourth terms of a proportion respectively. The first and fourth terms in a proportion i.e., a and d are called "extremes" and the second and third terms i.e., b and c are called "means".
Example: Find the extremes and means in 2:5 = 10:25. Directions: Answer the following questions. Also write at least ten examples of your own. 