A silk ribbon costs $5.60 for 0.8m. Find the constant of variation.

Answer: The constant of variation value of 7.

Step-by-step explanation: We are given cost of 0.8 meter of a silk ribbon = $5.60.

Let us assume y be the total cost for x meter of a silk ribbon and k is the constant of variation.

So, we can set up an equation for proportion relationship:

y = k x.

Let us plug x=0.8 and y = 5.60, in above proportion relationship equation, we get

5.60 = k (0.8).

Dividing both sides by 0.8, we get

5.60/0.8 = k (0.8) / 0.8

k = 7.

Therefore, the constant of variation value of 7.