Finding the Fourth Proportional to 12,391.78, 17,100.66 and 7,086.55

Step by Step Solution

1. Step 1: Write the proportion equation
   12,391.78 : 17,100.66 = 7,086.55 : x
2. Step 2: Convert to fraction form
   12,391.78/17,100.66 = 7,086.55/x
3. Step 3: Cross multiply
   12,391.78x = 17,100.66 × 7,086.55
4. Step 4: Simplify right side
   12,391.78x = 121,184,682.12
5. Step 5: Solve for x
   x = 121,184,682.12/12,391.78
6. Step 6: Final answer
   x = 9,779.44