Finding the Fourth Proportional to 42.17, 63.18 and 39.89

Step by Step Solution

1. Step 1: Write the proportion equation
   42.17 : 63.18 = 39.89 : x
2. Step 2: Convert to fraction form
   42.17/63.18 = 39.89/x
3. Step 3: Cross multiply
   42.17x = 63.18 × 39.89
4. Step 4: Simplify right side
   42.17x = 2,520.41
5. Step 5: Solve for x
   x = 2,520.41/42.17
6. Step 6: Final answer
   x = 59.77