Finding the Fourth Proportional to 82.71, 124.15 and 42.12

Step by Step Solution

1. Step 1: Write the proportion equation
   82.71 : 124.15 = 42.12 : x
2. Step 2: Convert to fraction form
   82.71/124.15 = 42.12/x
3. Step 3: Cross multiply
   82.71x = 124.15 × 42.12
4. Step 4: Simplify right side
   82.71x = 5,228.79
5. Step 5: Solve for x
   x = 5,228.79/82.71
6. Step 6: Final answer
   x = 63.22