Finding the Fourth Proportional to 100.72, 139.04 and 76.17

Step by Step Solution

1. Step 1: Write the proportion equation
   100.72 : 139.04 = 76.17 : x
2. Step 2: Convert to fraction form
   100.72/139.04 = 76.17/x
3. Step 3: Cross multiply
   100.72x = 139.04 × 76.17
4. Step 4: Simplify right side
   100.72x = 10,590.68
5. Step 5: Solve for x
   x = 10,590.68/100.72
6. Step 6: Final answer
   x = 105.15