Finding the Fourth Proportional to 78.77, 118.17 and 42.23

Step by Step Solution

1. Step 1: Write the proportion equation
   78.77 : 118.17 = 42.23 : x
2. Step 2: Convert to fraction form
   78.77/118.17 = 42.23/x
3. Step 3: Cross multiply
   78.77x = 118.17 × 42.23
4. Step 4: Simplify right side
   78.77x = 4,989.73
5. Step 5: Solve for x
   x = 4,989.73/78.77
6. Step 6: Final answer
   x = 63.35