Finding the Fourth Proportional to 82.28, 123.43 and 21.42

Step by Step Solution

1. Step 1: Write the proportion equation
   82.28 : 123.43 = 21.42 : x
2. Step 2: Convert to fraction form
   82.28/123.43 = 21.42/x
3. Step 3: Cross multiply
   82.28x = 123.43 × 21.42
4. Step 4: Simplify right side
   82.28x = 2,643.15
5. Step 5: Solve for x
   x = 2,643.15/82.28
6. Step 6: Final answer
   x = 32.12