Finding the Fourth Proportional to 82.86, 123.45 and 78.18

Step by Step Solution

1. Step 1: Write the proportion equation
   82.86 : 123.45 = 78.18 : x
2. Step 2: Convert to fraction form
   82.86/123.45 = 78.18/x
3. Step 3: Cross multiply
   82.86x = 123.45 × 78.18
4. Step 4: Simplify right side
   82.86x = 9,651.32
5. Step 5: Solve for x
   x = 9,651.32/82.86
6. Step 6: Final answer
   x = 116.48