Finding the Fourth Proportional to 51.86, 71.58 and 31.15

Step by Step Solution

1. Step 1: Write the proportion equation
   51.86 : 71.58 = 31.15 : x
2. Step 2: Convert to fraction form
   51.86/71.58 = 31.15/x
3. Step 3: Cross multiply
   51.86x = 71.58 × 31.15
4. Step 4: Simplify right side
   51.86x = 2,229.72
5. Step 5: Solve for x
   x = 2,229.72/51.86
6. Step 6: Final answer
   x = 42.99