Finding the Fourth Proportional to 1,116.86, 1,541.25 and 644.85

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.86 : 1,541.25 = 644.85 : x
2. Step 2: Convert to fraction form
   1,116.86/1,541.25 = 644.85/x
3. Step 3: Cross multiply
   1,116.86x = 1,541.25 × 644.85
4. Step 4: Simplify right side
   1,116.86x = 993,875.06
5. Step 5: Solve for x
   x = 993,875.06/1,116.86
6. Step 6: Final answer
   x = 889.89