Finding the Fourth Proportional to 78.54, 117.84 and 42.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78.54 : 117.84 = 42.50 : x
2. Step 2: Convert to fraction form
   78.54/117.84 = 42.50/x
3. Step 3: Cross multiply
   78.54x = 117.84 × 42.50
4. Step 4: Simplify right side
   78.54x = 5,007.61
5. Step 5: Solve for x
   x = 5,007.61/78.54
6. Step 6: Final answer
   x = 63.76