Finding the Fourth Proportional to 72.17, 108.56 and 71.56

Step by Step Solution

1. Step 1: Write the proportion equation
   72.17 : 108.56 = 71.56 : x
2. Step 2: Convert to fraction form
   72.17/108.56 = 71.56/x
3. Step 3: Cross multiply
   72.17x = 108.56 × 71.56
4. Step 4: Simplify right side
   72.17x = 7,768.55
5. Step 5: Solve for x
   x = 7,768.55/72.17
6. Step 6: Final answer
   x = 107.64