Finding the Fourth Proportional to 78.83, 118.07 and 42.15

Step by Step Solution

1. Step 1: Write the proportion equation
   78.83 : 118.07 = 42.15 : x
2. Step 2: Convert to fraction form
   78.83/118.07 = 42.15/x
3. Step 3: Cross multiply
   78.83x = 118.07 × 42.15
4. Step 4: Simplify right side
   78.83x = 4,976.44
5. Step 5: Solve for x
   x = 4,976.44/78.83
6. Step 6: Final answer
   x = 63.13