Finding the Fourth Proportional to 100,900.17, 139,243.16 and 55,578.30

Step by Step Solution

1. Step 1: Write the proportion equation
   100,900.17 : 139,243.16 = 55,578.30 : x
2. Step 2: Convert to fraction form
   100,900.17/139,243.16 = 55,578.30/x
3. Step 3: Cross multiply
   100,900.17x = 139,243.16 × 55,578.30
4. Step 4: Simplify right side
   100,900.17x = 7,738,898,119.43
5. Step 5: Solve for x
   x = 7,738,898,119.43/100,900.17
6. Step 6: Final answer
   x = 76,698.56