Finding the Fourth Proportional to 1,113.89, 1,670.68 and 613.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,113.89 : 1,670.68 = 613.72 : x
2. Step 2: Convert to fraction form
   1,113.89/1,670.68 = 613.72/x
3. Step 3: Cross multiply
   1,113.89x = 1,670.68 × 613.72
4. Step 4: Simplify right side
   1,113.89x = 1,025,329.73
5. Step 5: Solve for x
   x = 1,025,329.73/1,113.89
6. Step 6: Final answer
   x = 920.49