Finding the Fourth Proportional to 72.88, 108.78 and 67.18

Step by Step Solution

1. Step 1: Write the proportion equation
   72.88 : 108.78 = 67.18 : x
2. Step 2: Convert to fraction form
   72.88/108.78 = 67.18/x
3. Step 3: Cross multiply
   72.88x = 108.78 × 67.18
4. Step 4: Simplify right side
   72.88x = 7,307.84
5. Step 5: Solve for x
   x = 7,307.84/72.88
6. Step 6: Final answer
   x = 100.27