Finding the Fourth Proportional to 1,007.16, 1,388.52 and 861.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.16 : 1,388.52 = 861.36 : x
2. Step 2: Convert to fraction form
   1,007.16/1,388.52 = 861.36/x
3. Step 3: Cross multiply
   1,007.16x = 1,388.52 × 861.36
4. Step 4: Simplify right side
   1,007.16x = 1,196,015.59
5. Step 5: Solve for x
   x = 1,196,015.59/1,007.16
6. Step 6: Final answer
   x = 1,187.51