Finding the Fourth Proportional to 72,031.40, 99,405.39 and 39,768.09

Step by Step Solution

1. Step 1: Write the proportion equation
   72,031.40 : 99,405.39 = 39,768.09 : x
2. Step 2: Convert to fraction form
   72,031.40/99,405.39 = 39,768.09/x
3. Step 3: Cross multiply
   72,031.40x = 99,405.39 × 39,768.09
4. Step 4: Simplify right side
   72,031.40x = 3,953,162,496.01
5. Step 5: Solve for x
   x = 3,953,162,496.01/72,031.40
6. Step 6: Final answer
   x = 54,881.10