Finding the Fourth Proportional to 1,007.36, 1,386.27 and 978.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.36 : 1,386.27 = 978.81 : x
2. Step 2: Convert to fraction form
   1,007.36/1,386.27 = 978.81/x
3. Step 3: Cross multiply
   1,007.36x = 1,386.27 × 978.81
4. Step 4: Simplify right side
   1,007.36x = 1,356,894.94
5. Step 5: Solve for x
   x = 1,356,894.94/1,007.36
6. Step 6: Final answer
   x = 1,346.98