Finding the Fourth Proportional to 3,578.78, 4,938.71 and 1,985.51

Step by Step Solution

1. Step 1: Write the proportion equation
   3,578.78 : 4,938.71 = 1,985.51 : x
2. Step 2: Convert to fraction form
   3,578.78/4,938.71 = 1,985.51/x
3. Step 3: Cross multiply
   3,578.78x = 4,938.71 × 1,985.51
4. Step 4: Simplify right side
   3,578.78x = 9,805,823.47
5. Step 5: Solve for x
   x = 9,805,823.47/3,578.78
6. Step 6: Final answer
   x = 2,739.99