Finding the Fourth Proportional to 78.72, 108.69 and 49.66

Step by Step Solution

1. Step 1: Write the proportion equation
   78.72 : 108.69 = 49.66 : x
2. Step 2: Convert to fraction form
   78.72/108.69 = 49.66/x
3. Step 3: Cross multiply
   78.72x = 108.69 × 49.66
4. Step 4: Simplify right side
   78.72x = 5,397.30
5. Step 5: Solve for x
   x = 5,397.30/78.72
6. Step 6: Final answer
   x = 68.56