Finding the Fourth Proportional to 83.86, 125.72 and 82.78

Step by Step Solution

1. Step 1: Write the proportion equation
   83.86 : 125.72 = 82.78 : x
2. Step 2: Convert to fraction form
   83.86/125.72 = 82.78/x
3. Step 3: Cross multiply
   83.86x = 125.72 × 82.78
4. Step 4: Simplify right side
   83.86x = 10,407.10
5. Step 5: Solve for x
   x = 10,407.10/83.86
6. Step 6: Final answer
   x = 124.10