Finding the Fourth Proportional to 1,036.67, 1,430.71 and 638.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.67 : 1,430.71 = 638.30 : x
2. Step 2: Convert to fraction form
   1,036.67/1,430.71 = 638.30/x
3. Step 3: Cross multiply
   1,036.67x = 1,430.71 × 638.30
4. Step 4: Simplify right side
   1,036.67x = 913,224.17
5. Step 5: Solve for x
   x = 913,224.17/1,036.67
6. Step 6: Final answer
   x = 880.93