Finding the Fourth Proportional to 78.52, 117.85 and 42.47

Step by Step Solution

1. Step 1: Write the proportion equation
   78.52 : 117.85 = 42.47 : x
2. Step 2: Convert to fraction form
   78.52/117.85 = 42.47/x
3. Step 3: Cross multiply
   78.52x = 117.85 × 42.47
4. Step 4: Simplify right side
   78.52x = 5,005.09
5. Step 5: Solve for x
   x = 5,005.09/78.52
6. Step 6: Final answer
   x = 63.75