Finding the Fourth Proportional to 99,978, 137,969.80 and 55,266

Step by Step Solution

1. Step 1: Write the proportion equation
   99,978 : 137,969.80 = 55,266 : x
2. Step 2: Convert to fraction form
   99,978/137,969.80 = 55,266/x
3. Step 3: Cross multiply
   99,978x = 137,969.80 × 55,266
4. Step 4: Simplify right side
   99,978x = 7,625,038,966.80
5. Step 5: Solve for x
   x = 7,625,038,966.80/99,978
6. Step 6: Final answer
   x = 76,267.17