Finding the Fourth Proportional to 31,097.24, 42,920.82 and 20,487.80

Step by Step Solution

1. Step 1: Write the proportion equation
   31,097.24 : 42,920.82 = 20,487.80 : x
2. Step 2: Convert to fraction form
   31,097.24/42,920.82 = 20,487.80/x
3. Step 3: Cross multiply
   31,097.24x = 42,920.82 × 20,487.80
4. Step 4: Simplify right side
   31,097.24x = 879,353,176.00
5. Step 5: Solve for x
   x = 879,353,176.00/31,097.24
6. Step 6: Final answer
   x = 28,277.53