Finding the Fourth Proportional to 100.91, 139.31 and 73.31

Step by Step Solution

1. Step 1: Write the proportion equation
   100.91 : 139.31 = 73.31 : x
2. Step 2: Convert to fraction form
   100.91/139.31 = 73.31/x
3. Step 3: Cross multiply
   100.91x = 139.31 × 73.31
4. Step 4: Simplify right side
   100.91x = 10,211.75
5. Step 5: Solve for x
   x = 10,211.75/100.91
6. Step 6: Final answer
   x = 101.20