Finding the Fourth Proportional to 7,978.84, 11,017.22 and 7,138.04

Step by Step Solution

1. Step 1: Write the proportion equation
   7,978.84 : 11,017.22 = 7,138.04 : x
2. Step 2: Convert to fraction form
   7,978.84/11,017.22 = 7,138.04/x
3. Step 3: Cross multiply
   7,978.84x = 11,017.22 × 7,138.04
4. Step 4: Simplify right side
   7,978.84x = 78,641,357.05
5. Step 5: Solve for x
   x = 78,641,357.05/7,978.84
6. Step 6: Final answer
   x = 9,856.24