Finding the Fourth Proportional to 21,002.63, 31,504.55 and 5,420.25

Step by Step Solution

1. Step 1: Write the proportion equation
   21,002.63 : 31,504.55 = 5,420.25 : x
2. Step 2: Convert to fraction form
   21,002.63/31,504.55 = 5,420.25/x
3. Step 3: Cross multiply
   21,002.63x = 31,504.55 × 5,420.25
4. Step 4: Simplify right side
   21,002.63x = 170,762,510.04
5. Step 5: Solve for x
   x = 170,762,510.04/21,002.63
6. Step 6: Final answer
   x = 8,130.53