Finding the Fourth Proportional to 31,020.43, 42,785.28 and 19,680.16

Step by Step Solution

1. Step 1: Write the proportion equation
   31,020.43 : 42,785.28 = 19,680.16 : x
2. Step 2: Convert to fraction form
   31,020.43/42,785.28 = 19,680.16/x
3. Step 3: Cross multiply
   31,020.43x = 42,785.28 × 19,680.16
4. Step 4: Simplify right side
   31,020.43x = 842,021,156.04
5. Step 5: Solve for x
   x = 842,021,156.04/31,020.43
6. Step 6: Final answer
   x = 27,144.08