Finding the Fourth Proportional to 100.76, 139.06 and 77.48

Step by Step Solution

1. Step 1: Write the proportion equation
   100.76 : 139.06 = 77.48 : x
2. Step 2: Convert to fraction form
   100.76/139.06 = 77.48/x
3. Step 3: Cross multiply
   100.76x = 139.06 × 77.48
4. Step 4: Simplify right side
   100.76x = 10,774.37
5. Step 5: Solve for x
   x = 10,774.37/100.76
6. Step 6: Final answer
   x = 106.93