Finding the Fourth Proportional to 1,116.81, 1,541.27 and 644.79

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.81 : 1,541.27 = 644.79 : x
2. Step 2: Convert to fraction form
   1,116.81/1,541.27 = 644.79/x
3. Step 3: Cross multiply
   1,116.81x = 1,541.27 × 644.79
4. Step 4: Simplify right side
   1,116.81x = 993,792.26
5. Step 5: Solve for x
   x = 993,792.26/1,116.81
6. Step 6: Final answer
   x = 889.85