Finding the Fourth Proportional to 78.58, 118.42 and 78.58

Step by Step Solution

1. Step 1: Write the proportion equation
   78.58 : 118.42 = 78.58 : x
2. Step 2: Convert to fraction form
   78.58/118.42 = 78.58/x
3. Step 3: Cross multiply
   78.58x = 118.42 × 78.58
4. Step 4: Simplify right side
   78.58x = 9,305.44
5. Step 5: Solve for x
   x = 9,305.44/78.58
6. Step 6: Final answer
   x = 118.42