Finding the Fourth Proportional to 139.01, 191.78 and 83.75

Step by Step Solution

1. Step 1: Write the proportion equation
   139.01 : 191.78 = 83.75 : x
2. Step 2: Convert to fraction form
   139.01/191.78 = 83.75/x
3. Step 3: Cross multiply
   139.01x = 191.78 × 83.75
4. Step 4: Simplify right side
   139.01x = 16,060.20
5. Step 5: Solve for x
   x = 16,060.20/139.01
6. Step 6: Final answer
   x = 115.54