Constant of Proportionality Calculator
Find the constant of proportionality from tables, graphs, equations, or word problems.
k is the ratio of y to x (or the slope)
Enter a point (x, y) from a table or graph to find the constant of proportionality k.
How to use this calculator
Choose your input type (table, graph point, or equation) and enter the values. The calculator finds k = y ÷ x.
What this means in math class
The constant of proportionality k is the most tested concept in the proportional relationships unit. Every table, graph, and equation question asks for it.
Worked examples
Example 1: From a table
Table: x=2,y=8 and x=5,y=20
- Step 1:Pick any row: x=2, y=8
- Step 2:Divide y by x: 8 ÷ 2 = 4
- Step 3:Check another row: 20 ÷ 5 = 4
- Step 4:k = 4, equation: y = 4x
Example 2: From a graph
Line passes through (4, 12)
- Step 1:Pick the point: (4, 12)
- Step 2:Divide y by x: 12 ÷ 4 = 3
- Step 3:k = 3
Example 3: From a word problem
A car travels 60 miles per hour
- Step 1:The rate is 60 miles per 1 hour
- Step 2:k = 60
- Step 3:Equation: y = 60x
Frequently asked questions
What is the constant of proportionality?
It is the fixed number k in y = kx that relates y to x.
Is k always positive?
No. k can be negative, which means y decreases as x increases.
What is the difference between k and slope?
In a proportional relationship, k and slope are the same number.
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