Finding the Fourth Proportional to 1,036.94, 1,430.46 and 638.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.94 : 1,430.46 = 638.72 : x
2. Step 2: Convert to fraction form
   1,036.94/1,430.46 = 638.72/x
3. Step 3: Cross multiply
   1,036.94x = 1,430.46 × 638.72
4. Step 4: Simplify right side
   1,036.94x = 913,661.62
5. Step 5: Solve for x
   x = 913,661.62/1,036.94
6. Step 6: Final answer
   x = 881.12