Finding the Fourth Proportional to 1,116.79, 1,541.03 and 644.76

Step by Step Solution

1. Step 1: Write the proportion equation
   1,116.79 : 1,541.03 = 644.76 : x
2. Step 2: Convert to fraction form
   1,116.79/1,541.03 = 644.76/x
3. Step 3: Cross multiply
   1,116.79x = 1,541.03 × 644.76
4. Step 4: Simplify right side
   1,116.79x = 993,591.28
5. Step 5: Solve for x
   x = 993,591.28/1,116.79
6. Step 6: Final answer
   x = 889.69