Finding the Fourth Proportional to 42.12, 62.78 and 42.05

Step by Step Solution

1. Step 1: Write the proportion equation
   42.12 : 62.78 = 42.05 : x
2. Step 2: Convert to fraction form
   42.12/62.78 = 42.05/x
3. Step 3: Cross multiply
   42.12x = 62.78 × 42.05
4. Step 4: Simplify right side
   42.12x = 2,639.85
5. Step 5: Solve for x
   x = 2,639.85/42.12
6. Step 6: Final answer
   x = 62.67