Finding the Fourth Proportional to 144.80, 217.21 and 42.10

Step by Step Solution

1. Step 1: Write the proportion equation
   144.80 : 217.21 = 42.10 : x
2. Step 2: Convert to fraction form
   144.80/217.21 = 42.10/x
3. Step 3: Cross multiply
   144.80x = 217.21 × 42.10
4. Step 4: Simplify right side
   144.80x = 9,143.89
5. Step 5: Solve for x
   x = 9,143.89/144.80
6. Step 6: Final answer
   x = 63.15