Finding the Fourth Proportional to 42.39, 63.59 and 31.12

Step by Step Solution

1. Step 1: Write the proportion equation
   42.39 : 63.59 = 31.12 : x
2. Step 2: Convert to fraction form
   42.39/63.59 = 31.12/x
3. Step 3: Cross multiply
   42.39x = 63.59 × 31.12
4. Step 4: Simplify right side
   42.39x = 1,978.92
5. Step 5: Solve for x
   x = 1,978.92/42.39
6. Step 6: Final answer
   x = 46.68