Finding the Fourth Proportional to 1,002.15, 1,383.20 and 609.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,002.15 : 1,383.20 = 609.10 : x
2. Step 2: Convert to fraction form
   1,002.15/1,383.20 = 609.10/x
3. Step 3: Cross multiply
   1,002.15x = 1,383.20 × 609.10
4. Step 4: Simplify right side
   1,002.15x = 842,505.18
5. Step 5: Solve for x
   x = 842,505.18/1,002.15
6. Step 6: Final answer
   x = 840.70