Finding the Fourth Proportional to 30,728.28, 42,402.32 and 17,115.30

Step by Step Solution

1. Step 1: Write the proportion equation
   30,728.28 : 42,402.32 = 17,115.30 : x
2. Step 2: Convert to fraction form
   30,728.28/42,402.32 = 17,115.30/x
3. Step 3: Cross multiply
   30,728.28x = 42,402.32 × 17,115.30
4. Step 4: Simplify right side
   30,728.28x = 725,728,427.50
5. Step 5: Solve for x
   x = 725,728,427.50/30,728.28
6. Step 6: Final answer
   x = 23,617.61