Finding the Fourth Proportional to 78.42, 117.42 and 42.36

Step by Step Solution

1. Step 1: Write the proportion equation
   78.42 : 117.42 = 42.36 : x
2. Step 2: Convert to fraction form
   78.42/117.42 = 42.36/x
3. Step 3: Cross multiply
   78.42x = 117.42 × 42.36
4. Step 4: Simplify right side
   78.42x = 4,973.91
5. Step 5: Solve for x
   x = 4,973.91/78.42
6. Step 6: Final answer
   x = 63.43