A veterinarian knows that a 50-pound dog gets 0.5 milligram of a certain medicine, and that the number of milligrams, m, varies directly with the weight of the dog, w. The vet uses these steps to find the amount of medicine to give a 10-pound dog. Veterinarian's Work Step 1 Find the constant of variation. k is equal to 0 point 5 over 50 is equal to 0 point 0 1 Step 2 Write the direct variation equation. m is equal to 0 point 0 1 w Step 3 Substitute 10 into the equation to find the dosage for a 10 -pound dog. 10 is equal to 0 point 0 1 w Step 4 Solve for w 10 is equal to 0 point 0 1 w w is equal to 1000 The 10 -pound dog needs 1000 milligrams. In which step did the veterinarian make the first error?