Finding the Fourth Proportional to 83.81, 125.79 and 42.71

Step by Step Solution

1. Step 1: Write the proportion equation
   83.81 : 125.79 = 42.71 : x
2. Step 2: Convert to fraction form
   83.81/125.79 = 42.71/x
3. Step 3: Cross multiply
   83.81x = 125.79 × 42.71
4. Step 4: Simplify right side
   83.81x = 5,371.82
5. Step 5: Solve for x
   x = 5,371.82/83.81
6. Step 6: Final answer
   x = 64.10