Overview
In inverse proportion, increasing x decreases y. If y = 10 when x = 4, the constant is 40, and when x = 8, y becomes 5. This relationship is common in speed, time and work distribution.
Formula
y = k ÷ x, where k = x1 × y1. Therefore, y2 = k ÷ x2.
How it works
1
Enter the known pair
x1 and y1 from the first case.
2
Calculate the constant
Multiply x1 by y1.
3
Enter x2
Divide the constant by x2 to get y2.
Worked examples
Example 1: 4 → 10, and 8 → ?
k = 40, so y2 = 5.
Example 2: 2 → 12, and 6 → ?
k = 24, so y2 = 4.
Frequently asked questions
How do I know the relationship is inverse?
It is inverse if the product x × y is constant.
Can the values be negative?
Yes, but zero is rejected because division by zero is undefined.
What is a real example of inverse proportion?
The relationship between speed and time for a fixed distance: as speed increases, time decreases.
This calculator is for educational and informational purposes only and is not a substitute for professional advice.