Finding the Fourth Proportional to 83.10, 124.72 and 42.55

Step by Step Solution

1. Step 1: Write the proportion equation
   83.10 : 124.72 = 42.55 : x
2. Step 2: Convert to fraction form
   83.10/124.72 = 42.55/x
3. Step 3: Cross multiply
   83.10x = 124.72 × 42.55
4. Step 4: Simplify right side
   83.10x = 5,306.21
5. Step 5: Solve for x
   x = 5,306.21/83.10
6. Step 6: Final answer
   x = 63.86