Finding the Fourth Proportional to 100.62, 139.05 and 76.05

Step by Step Solution

1. Step 1: Write the proportion equation
   100.62 : 139.05 = 76.05 : x
2. Step 2: Convert to fraction form
   100.62/139.05 = 76.05/x
3. Step 3: Cross multiply
   100.62x = 139.05 × 76.05
4. Step 4: Simplify right side
   100.62x = 10,574.75
5. Step 5: Solve for x
   x = 10,574.75/100.62
6. Step 6: Final answer
   x = 105.10