Finding the Fourth Proportional to 12,697.56, 17,516.66 and 7,978.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,697.56 : 17,516.66 = 7,978.50 : x
2. Step 2: Convert to fraction form
   12,697.56/17,516.66 = 7,978.50/x
3. Step 3: Cross multiply
   12,697.56x = 17,516.66 × 7,978.50
4. Step 4: Simplify right side
   12,697.56x = 139,756,631.92
5. Step 5: Solve for x
   x = 139,756,631.92/12,697.56
6. Step 6: Final answer
   x = 11,006.57