Finding the Fourth Proportional to 100,985.98, 139,354.31 and 55,661.47

Step by Step Solution

1. Step 1: Write the proportion equation
   100,985.98 : 139,354.31 = 55,661.47 : x
2. Step 2: Convert to fraction form
   100,985.98/139,354.31 = 55,661.47/x
3. Step 3: Cross multiply
   100,985.98x = 139,354.31 × 55,661.47
4. Step 4: Simplify right side
   100,985.98x = 7,756,665,536.20
5. Step 5: Solve for x
   x = 7,756,665,536.20/100,985.98
6. Step 6: Final answer
   x = 76,809.33