Finding the Fourth Proportional to 42.31, 63.31 and 31.98

Step by Step Solution

1. Step 1: Write the proportion equation
   42.31 : 63.31 = 31.98 : x
2. Step 2: Convert to fraction form
   42.31/63.31 = 31.98/x
3. Step 3: Cross multiply
   42.31x = 63.31 × 31.98
4. Step 4: Simplify right side
   42.31x = 2,024.65
5. Step 5: Solve for x
   x = 2,024.65/42.31
6. Step 6: Final answer
   x = 47.85