Finding the Fourth Proportional to 78.72, 108.75 and 67.18

Step by Step Solution

1. Step 1: Write the proportion equation
   78.72 : 108.75 = 67.18 : x
2. Step 2: Convert to fraction form
   78.72/108.75 = 67.18/x
3. Step 3: Cross multiply
   78.72x = 108.75 × 67.18
4. Step 4: Simplify right side
   78.72x = 7,306.21
5. Step 5: Solve for x
   x = 7,306.21/78.72
6. Step 6: Final answer
   x = 92.81