Proportion
Definition of Proportion
A proportion is an equation written in the form stating that two ratios are equivalent.
In other words, two sets of numbers are proportional if one set is a constant times the other.
Video Examples: What is a Proportion?
Example of Proportion

,
are examples of proportions.
Solved Example on Proportion
Ques: A cardboard model of a Honda bike is part of an outdoor display. Its height is 4 ft. The actual Honda bike is 5 ft long and 2 ft high. Find the length of the model, if its dimensions are proportionate to the real bike.
Choices:
A. 11 ftB. 12 ft
C. 9 ft
D. 10 ft
Correct Answer: D
Solution:

Step 1: Let n be the length of Honda bike cardboard model.
Step 2: [Write a proportion.]
Step 3: n × 2 = 4 × 5 [Write the cross products.]
Step 4: n = 10 [Simplify the expression.]
Step 5: The length of the Honda bike cardboard model is 10 ft.
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