how do I know how to find the constant of the proportianlity
Lance is knitting a blanket and needs to buy some more yarn. At his local craft store, 2 balls of yarn cost $5 and 8 balls of yarn cost $20. What is the constant of proportionality in this direct variation situation?
A.
B.
C.
D.
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To find the constant of proportionality in this direct variation situation, we need to set up a proportion using the given values.
Let's let x represent the number of balls of yarn and y represent the cost in dollars.
From the information given, we can set up the following proportion:
2/5 = 8/20
Now, we can cross-multiply to solve for x:
20 * 2 = 5 * 8
40 = 40
Therefore, the constant of proportionality is 2.
So, the correct answer is A.