Finding the Fourth Proportional to 100.89, 139.10 and 74.61

Step by Step Solution

1. Step 1: Write the proportion equation
   100.89 : 139.10 = 74.61 : x
2. Step 2: Convert to fraction form
   100.89/139.10 = 74.61/x
3. Step 3: Cross multiply
   100.89x = 139.10 × 74.61
4. Step 4: Simplify right side
   100.89x = 10,377.88
5. Step 5: Solve for x
   x = 10,377.88/100.89
6. Step 6: Final answer
   x = 102.86