Finding the Fourth Proportional to 139.06, 191.89 and 76.89

Step by Step Solution

1. Step 1: Write the proportion equation
   139.06 : 191.89 = 76.89 : x
2. Step 2: Convert to fraction form
   139.06/191.89 = 76.89/x
3. Step 3: Cross multiply
   139.06x = 191.89 × 76.89
4. Step 4: Simplify right side
   139.06x = 14,754.42
5. Step 5: Solve for x
   x = 14,754.42/139.06
6. Step 6: Final answer
   x = 106.10