Finding the Fourth Proportional to 1,985.33, 2,978.33 and 669.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,985.33 : 2,978.33 = 669.20 : x
2. Step 2: Convert to fraction form
   1,985.33/2,978.33 = 669.20/x
3. Step 3: Cross multiply
   1,985.33x = 2,978.33 × 669.20
4. Step 4: Simplify right side
   1,985.33x = 1,993,080.20
5. Step 5: Solve for x
   x = 1,993,080.20/1,985.33
6. Step 6: Final answer
   x = 1,003.91