Finding the Fourth Proportional to 31,112.72, 42,907.20 and 20,498.48

Step by Step Solution

1. Step 1: Write the proportion equation
   31,112.72 : 42,907.20 = 20,498.48 : x
2. Step 2: Convert to fraction form
   31,112.72/42,907.20 = 20,498.48/x
3. Step 3: Cross multiply
   31,112.72x = 42,907.20 × 20,498.48
4. Step 4: Simplify right side
   31,112.72x = 879,532,381.06
5. Step 5: Solve for x
   x = 879,532,381.06/31,112.72
6. Step 6: Final answer
   x = 28,269.22