Finding the Fourth Proportional to 78.86, 118.34 and 42.82

Step by Step Solution

1. Step 1: Write the proportion equation
   78.86 : 118.34 = 42.82 : x
2. Step 2: Convert to fraction form
   78.86/118.34 = 42.82/x
3. Step 3: Cross multiply
   78.86x = 118.34 × 42.82
4. Step 4: Simplify right side
   78.86x = 5,067.13
5. Step 5: Solve for x
   x = 5,067.13/78.86
6. Step 6: Final answer
   x = 64.25