Finding the Fourth Proportional to 82.42, 123.61 and 21.55

Step by Step Solution

1. Step 1: Write the proportion equation
   82.42 : 123.61 = 21.55 : x
2. Step 2: Convert to fraction form
   82.42/123.61 = 21.55/x
3. Step 3: Cross multiply
   82.42x = 123.61 × 21.55
4. Step 4: Simplify right side
   82.42x = 2,663.18
5. Step 5: Solve for x
   x = 2,663.18/82.42
6. Step 6: Final answer
   x = 32.31