Finding the Fourth Proportional to 71,780.63, 99,061.15 and 39,950.21

Step by Step Solution

1. Step 1: Write the proportion equation
   71,780.63 : 99,061.15 = 39,950.21 : x
2. Step 2: Convert to fraction form
   71,780.63/99,061.15 = 39,950.21/x
3. Step 3: Cross multiply
   71,780.63x = 99,061.15 × 39,950.21
4. Step 4: Simplify right side
   71,780.63x = 3,957,514,080.39
5. Step 5: Solve for x
   x = 3,957,514,080.39/71,780.63
6. Step 6: Final answer
   x = 55,133.45