Finding the Fourth Proportional to 78.77, 118.02 and 42.73

Step by Step Solution

1. Step 1: Write the proportion equation
   78.77 : 118.02 = 42.73 : x
2. Step 2: Convert to fraction form
   78.77/118.02 = 42.73/x
3. Step 3: Cross multiply
   78.77x = 118.02 × 42.73
4. Step 4: Simplify right side
   78.77x = 5,042.86
5. Step 5: Solve for x
   x = 5,042.86/78.77
6. Step 6: Final answer
   x = 64.02