Finding the Fourth Proportional to 12,428.74, 17,155.28 and 9,928.27

Step by Step Solution

1. Step 1: Write the proportion equation
   12,428.74 : 17,155.28 = 9,928.27 : x
2. Step 2: Convert to fraction form
   12,428.74/17,155.28 = 9,928.27/x
3. Step 3: Cross multiply
   12,428.74x = 17,155.28 × 9,928.27
4. Step 4: Simplify right side
   12,428.74x = 170,322,116.35
5. Step 5: Solve for x
   x = 170,322,116.35/12,428.74
6. Step 6: Final answer
   x = 13,703.90