Finding the Fourth Proportional to 12,456.79, 17,190.43 and 7,420.01

Step by Step Solution

1. Step 1: Write the proportion equation
   12,456.79 : 17,190.43 = 7,420.01 : x
2. Step 2: Convert to fraction form
   12,456.79/17,190.43 = 7,420.01/x
3. Step 3: Cross multiply
   12,456.79x = 17,190.43 × 7,420.01
4. Step 4: Simplify right side
   12,456.79x = 127,553,058.00
5. Step 5: Solve for x
   x = 127,553,058.00/12,456.79
6. Step 6: Final answer
   x = 10,239.64