Finding the Fourth Proportional to 12,420.15, 17,131.12 and 8,434.34

Step by Step Solution

1. Step 1: Write the proportion equation
   12,420.15 : 17,131.12 = 8,434.34 : x
2. Step 2: Convert to fraction form
   12,420.15/17,131.12 = 8,434.34/x
3. Step 3: Cross multiply
   12,420.15x = 17,131.12 × 8,434.34
4. Step 4: Simplify right side
   12,420.15x = 144,489,690.66
5. Step 5: Solve for x
   x = 144,489,690.66/12,420.15
6. Step 6: Final answer
   x = 11,633.49