Finding the Fourth Proportional to 1,007.39, 1,389.56 and 634.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.39 : 1,389.56 = 634.05 : x
2. Step 2: Convert to fraction form
   1,007.39/1,389.56 = 634.05/x
3. Step 3: Cross multiply
   1,007.39x = 1,389.56 × 634.05
4. Step 4: Simplify right side
   1,007.39x = 881,047.35
5. Step 5: Solve for x
   x = 881,047.35/1,007.39
6. Step 6: Final answer
   x = 874.59