Finding the Fourth Proportional to 128.59, 192.61 and 82.79

Step by Step Solution

1. Step 1: Write the proportion equation
   128.59 : 192.61 = 82.79 : x
2. Step 2: Convert to fraction form
   128.59/192.61 = 82.79/x
3. Step 3: Cross multiply
   128.59x = 192.61 × 82.79
4. Step 4: Simplify right side
   128.59x = 15,945.77
5. Step 5: Solve for x
   x = 15,945.77/128.59
6. Step 6: Final answer
   x = 124.00