Finding the Fourth Proportional to 100.79, 139.28 and 76.18

Step by Step Solution

1. Step 1: Write the proportion equation
   100.79 : 139.28 = 76.18 : x
2. Step 2: Convert to fraction form
   100.79/139.28 = 76.18/x
3. Step 3: Cross multiply
   100.79x = 139.28 × 76.18
4. Step 4: Simplify right side
   100.79x = 10,610.35
5. Step 5: Solve for x
   x = 10,610.35/100.79
6. Step 6: Final answer
   x = 105.27