Finding the Fourth Proportional to 78.42, 117.67 and 42.34

Step by Step Solution

1. Step 1: Write the proportion equation
   78.42 : 117.67 = 42.34 : x
2. Step 2: Convert to fraction form
   78.42/117.67 = 42.34/x
3. Step 3: Cross multiply
   78.42x = 117.67 × 42.34
4. Step 4: Simplify right side
   78.42x = 4,982.15
5. Step 5: Solve for x
   x = 4,982.15/78.42
6. Step 6: Final answer
   x = 63.53