Finding the Fourth Proportional to 42.50, 64.02 and 31.88

Step by Step Solution

1. Step 1: Write the proportion equation
   42.50 : 64.02 = 31.88 : x
2. Step 2: Convert to fraction form
   42.50/64.02 = 31.88/x
3. Step 3: Cross multiply
   42.50x = 64.02 × 31.88
4. Step 4: Simplify right side
   42.50x = 2,040.52
5. Step 5: Solve for x
   x = 2,040.52/42.50
6. Step 6: Final answer
   x = 48.02