Finding the Fourth Proportional to 12,999.63, 17,939.43 and 7,031.31

Step by Step Solution

1. Step 1: Write the proportion equation
   12,999.63 : 17,939.43 = 7,031.31 : x
2. Step 2: Convert to fraction form
   12,999.63/17,939.43 = 7,031.31/x
3. Step 3: Cross multiply
   12,999.63x = 17,939.43 × 7,031.31
4. Step 4: Simplify right side
   12,999.63x = 126,137,693.55
5. Step 5: Solve for x
   x = 126,137,693.55/12,999.63
6. Step 6: Final answer
   x = 9,703.18