Finding the Fourth Proportional to 72.78, 109.07 and 72.63

Step by Step Solution

1. Step 1: Write the proportion equation
   72.78 : 109.07 = 72.63 : x
2. Step 2: Convert to fraction form
   72.78/109.07 = 72.63/x
3. Step 3: Cross multiply
   72.78x = 109.07 × 72.63
4. Step 4: Simplify right side
   72.78x = 7,921.39
5. Step 5: Solve for x
   x = 7,921.39/72.78
6. Step 6: Final answer
   x = 108.84