Finding the Third Proportional to 8,421.47 and 13,490.30

Step by Step Solution

1. Step 1: Write the proportion equation
   8,421.47 : 13,490.30 = 13,490.30 : x
2. Step 2: Convert to fraction form
   8,421.47/13,490.30 = 13,490.30/x
3. Step 3: Cross multiply
   8,421.47x = 13,490.30 × 13,490.30
4. Step 4: Simplify right side
   8,421.47x = 181,988,109.78
5. Step 5: Solve for x
   x = 181,988,109.78/8,421.47
6. Step 6: Final answer
   x = 21,610.02