Finding the Fourth Proportional to 99,997.90, 137,999.10 and 54,678.72

Step by Step Solution

1. Step 1: Write the proportion equation
   99,997.90 : 137,999.10 = 54,678.72 : x
2. Step 2: Convert to fraction form
   99,997.90/137,999.10 = 54,678.72/x
3. Step 3: Cross multiply
   99,997.90x = 137,999.10 × 54,678.72
4. Step 4: Simplify right side
   99,997.90x = 7,545,614,149.15
5. Step 5: Solve for x
   x = 7,545,614,149.15/99,997.90
6. Step 6: Final answer
   x = 75,457.73