Finding the Fourth Proportional to 1,123,432.56, 1,550,219.76 and 639,896.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123,432.56 : 1,550,219.76 = 639,896.40 : x
2. Step 2: Convert to fraction form
   1,123,432.56/1,550,219.76 = 639,896.40/x
3. Step 3: Cross multiply
   1,123,432.56x = 1,550,219.76 × 639,896.40
4. Step 4: Simplify right side
   1,123,432.56x = 991,980,043,632.86
5. Step 5: Solve for x
   x = 991,980,043,632.86/1,123,432.56
6. Step 6: Final answer
   x = 882,990.29