Finding the Fourth Proportional to 1,008.72, 1,395.72 and 878.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,008.72 : 1,395.72 = 878.16 : x
2. Step 2: Convert to fraction form
   1,008.72/1,395.72 = 878.16/x
3. Step 3: Cross multiply
   1,008.72x = 1,395.72 × 878.16
4. Step 4: Simplify right side
   1,008.72x = 1,225,665.48
5. Step 5: Solve for x
   x = 1,225,665.48/1,008.72
6. Step 6: Final answer
   x = 1,215.07