Finding the Fourth Proportional to 100.89, 139.29 and 71.73

Step by Step Solution

1. Step 1: Write the proportion equation
   100.89 : 139.29 = 71.73 : x
2. Step 2: Convert to fraction form
   100.89/139.29 = 71.73/x
3. Step 3: Cross multiply
   100.89x = 139.29 × 71.73
4. Step 4: Simplify right side
   100.89x = 9,991.27
5. Step 5: Solve for x
   x = 9,991.27/100.89
6. Step 6: Final answer
   x = 99.03