Finding the Fourth Proportional to 72.96, 109.42 and 21.61

Step by Step Solution

1. Step 1: Write the proportion equation
   72.96 : 109.42 = 21.61 : x
2. Step 2: Convert to fraction form
   72.96/109.42 = 21.61/x
3. Step 3: Cross multiply
   72.96x = 109.42 × 21.61
4. Step 4: Simplify right side
   72.96x = 2,364.57
5. Step 5: Solve for x
   x = 2,364.57/72.96
6. Step 6: Final answer
   x = 32.41