Finding the Fourth Proportional to 1,015.72, 1,402.02 and 617.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,015.72 : 1,402.02 = 617.60 : x
2. Step 2: Convert to fraction form
   1,015.72/1,402.02 = 617.60/x
3. Step 3: Cross multiply
   1,015.72x = 1,402.02 × 617.60
4. Step 4: Simplify right side
   1,015.72x = 865,887.55
5. Step 5: Solve for x
   x = 865,887.55/1,015.72
6. Step 6: Final answer
   x = 852.49