Finding the Fourth Proportional to 1,008.38, 1,392.42 and 635.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.38 : 1,392.42 = 635.99 : x
2. Step 2: Convert to fraction form
   1,008.38/1,392.42 = 635.99/x
3. Step 3: Cross multiply
   1,008.38x = 1,392.42 × 635.99
4. Step 4: Simplify right side
   1,008.38x = 885,558.23
5. Step 5: Solve for x
   x = 885,558.23/1,008.38
6. Step 6: Final answer
   x = 878.20