Finding the Fourth Proportional to 78.72, 118.17 and 49.89

Step by Step Solution

1. Step 1: Write the proportion equation
   78.72 : 118.17 = 49.89 : x
2. Step 2: Convert to fraction form
   78.72/118.17 = 49.89/x
3. Step 3: Cross multiply
   78.72x = 118.17 × 49.89
4. Step 4: Simplify right side
   78.72x = 5,895.50
5. Step 5: Solve for x
   x = 5,895.50/78.72
6. Step 6: Final answer
   x = 74.89