Finding the Fourth Proportional to 1,665.98, 2,498.68 and 611.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,665.98 : 2,498.68 = 611.57 : x
2. Step 2: Convert to fraction form
   1,665.98/2,498.68 = 611.57/x
3. Step 3: Cross multiply
   1,665.98x = 2,498.68 × 611.57
4. Step 4: Simplify right side
   1,665.98x = 1,528,117.73
5. Step 5: Solve for x
   x = 1,528,117.73/1,665.98
6. Step 6: Final answer
   x = 917.25