Finding the Fourth Proportional to 1,036.83, 1,430.53 and 638.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.83 : 1,430.53 = 638.55 : x
2. Step 2: Convert to fraction form
   1,036.83/1,430.53 = 638.55/x
3. Step 3: Cross multiply
   1,036.83x = 1,430.53 × 638.55
4. Step 4: Simplify right side
   1,036.83x = 913,463.34
5. Step 5: Solve for x
   x = 913,463.34/1,036.83
6. Step 6: Final answer
   x = 881.01