Finding the Fourth Proportional to 8,408.58, 12,656.72 and 7,140.12

Step by Step Solution

1. Step 1: Write the proportion equation
   8,408.58 : 12,656.72 = 7,140.12 : x
2. Step 2: Convert to fraction form
   8,408.58/12,656.72 = 7,140.12/x
3. Step 3: Cross multiply
   8,408.58x = 12,656.72 × 7,140.12
4. Step 4: Simplify right side
   8,408.58x = 90,370,463.91
5. Step 5: Solve for x
   x = 90,370,463.91/8,408.58
6. Step 6: Final answer
   x = 10,747.41