Finding the Fourth Proportional to 78.66, 108.18 and 72.72

Step by Step Solution

1. Step 1: Write the proportion equation
   78.66 : 108.18 = 72.72 : x
2. Step 2: Convert to fraction form
   78.66/108.18 = 72.72/x
3. Step 3: Cross multiply
   78.66x = 108.18 × 72.72
4. Step 4: Simplify right side
   78.66x = 7,866.85
5. Step 5: Solve for x
   x = 7,866.85/78.66
6. Step 6: Final answer
   x = 100.01