Finding the Fourth Proportional to 72.78, 109.17 and 64.14

Step by Step Solution

1. Step 1: Write the proportion equation
   72.78 : 109.17 = 64.14 : x
2. Step 2: Convert to fraction form
   72.78/109.17 = 64.14/x
3. Step 3: Cross multiply
   72.78x = 109.17 × 64.14
4. Step 4: Simplify right side
   72.78x = 7,002.16
5. Step 5: Solve for x
   x = 7,002.16/72.78
6. Step 6: Final answer
   x = 96.21