Finding the Fourth Proportional to 78.67, 118.18 and 68.42

Step by Step Solution

1. Step 1: Write the proportion equation
   78.67 : 118.18 = 68.42 : x
2. Step 2: Convert to fraction form
   78.67/118.18 = 68.42/x
3. Step 3: Cross multiply
   78.67x = 118.18 × 68.42
4. Step 4: Simplify right side
   78.67x = 8,085.51
5. Step 5: Solve for x
   x = 8,085.51/78.67
6. Step 6: Final answer
   x = 102.78