Finding the Fourth Proportional to 72.84, 108.72 and 71.64

Step by Step Solution

1. Step 1: Write the proportion equation
   72.84 : 108.72 = 71.64 : x
2. Step 2: Convert to fraction form
   72.84/108.72 = 71.64/x
3. Step 3: Cross multiply
   72.84x = 108.72 × 71.64
4. Step 4: Simplify right side
   72.84x = 7,788.70
5. Step 5: Solve for x
   x = 7,788.70/72.84
6. Step 6: Final answer
   x = 106.93