Finding the Fourth Proportional to 1,150.78, 1,588.20 and 1,007.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,150.78 : 1,588.20 = 1,007.68 : x
2. Step 2: Convert to fraction form
   1,150.78/1,588.20 = 1,007.68/x
3. Step 3: Cross multiply
   1,150.78x = 1,588.20 × 1,007.68
4. Step 4: Simplify right side
   1,150.78x = 1,600,397.38
5. Step 5: Solve for x
   x = 1,600,397.38/1,150.78
6. Step 6: Final answer
   x = 1,390.71