Finding the Fourth Proportional to 72.49, 108.72 and 31.88

Step by Step Solution

1. Step 1: Write the proportion equation
   72.49 : 108.72 = 31.88 : x
2. Step 2: Convert to fraction form
   72.49/108.72 = 31.88/x
3. Step 3: Cross multiply
   72.49x = 108.72 × 31.88
4. Step 4: Simplify right side
   72.49x = 3,465.99
5. Step 5: Solve for x
   x = 3,465.99/72.49
6. Step 6: Final answer
   x = 47.82