Finding the Fourth Proportional to 20,111.30, 30,161.55 and 8,422.10

Step by Step Solution

1. Step 1: Write the proportion equation
   20,111.30 : 30,161.55 = 8,422.10 : x
2. Step 2: Convert to fraction form
   20,111.30/30,161.55 = 8,422.10/x
3. Step 3: Cross multiply
   20,111.30x = 30,161.55 × 8,422.10
4. Step 4: Simplify right side
   20,111.30x = 254,023,590.26
5. Step 5: Solve for x
   x = 254,023,590.26/20,111.30
6. Step 6: Final answer
   x = 12,630.89