Finding the Fourth Proportional to 102.86, 141.78 and 82.10

Step by Step Solution

1. Step 1: Write the proportion equation
   102.86 : 141.78 = 82.10 : x
2. Step 2: Convert to fraction form
   102.86/141.78 = 82.10/x
3. Step 3: Cross multiply
   102.86x = 141.78 × 82.10
4. Step 4: Simplify right side
   102.86x = 11,640.80
5. Step 5: Solve for x
   x = 11,640.80/102.86
6. Step 6: Final answer
   x = 113.17