Constructing proportions to solve application problems

Constructing proportions to solve application problems Ratio and proportion is one of the basic topics in math. Proportion is constructed to solve word problems or a questions where quantities maintain a fixed ratio or the same fractional value. . In such cases the question can be analyzed and the fixed ratio can be calculated. Proportionality always maintains a fixed ratio or fraction between two quantities. For example, a / b = c / d. It can be written as a : b = c : d. When things are in proportion their relative sizes are the same. Example 1: Do these form ratio and proportion? A basket has10 apples and 5 oranges. Another basket has 30 apples and 15 oranges. Solution: The number of apples and oranges in the baskets are to be compared. The ratio can be expressed as: First basket: Number of apples/ Number of oranges = 10/5 = 2/1. Second basket: Number of apples/ Number of oranges = 30/15 = 2/1. The ratios are the same hence they form a proportion. Question: Multiple choice question (Pick the correct option.) Find the k in the proportion k : 3 = 4 : 3? a) 3 b) 12 c) 4 d) None of these. Correct answer: option c Explanation: The proportion can be expressed in a fraction in the form. This gives, k/3 = 4/3. Now multiply both sides of the equation by 3. This gives 3(k/ 3) = (4/3) * (3); k = 4. Hence the value of k for the given proportion is 4.