Finding the Fourth Proportional to 1,007.56, 1,389.78 and 658.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.56 : 1,389.78 = 658.12 : x
2. Step 2: Convert to fraction form
   1,007.56/1,389.78 = 658.12/x
3. Step 3: Cross multiply
   1,007.56x = 1,389.78 × 658.12
4. Step 4: Simplify right side
   1,007.56x = 914,642.01
5. Step 5: Solve for x
   x = 914,642.01/1,007.56
6. Step 6: Final answer
   x = 907.78