Finding the Fourth Proportional to 12,622.72, 17,416.56 and 8,428

Step by Step Solution

1. Step 1: Write the proportion equation
   12,622.72 : 17,416.56 = 8,428 : x
2. Step 2: Convert to fraction form
   12,622.72/17,416.56 = 8,428/x
3. Step 3: Cross multiply
   12,622.72x = 17,416.56 × 8,428
4. Step 4: Simplify right side
   12,622.72x = 146,786,767.68
5. Step 5: Solve for x
   x = 146,786,767.68/12,622.72
6. Step 6: Final answer
   x = 11,628.77