Finding the Fourth Proportional to 20,870.43, 31,313.34 and 9,780.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,870.43 : 31,313.34 = 9,780.72 : x
2. Step 2: Convert to fraction form
   20,870.43/31,313.34 = 9,780.72/x
3. Step 3: Cross multiply
   20,870.43x = 31,313.34 × 9,780.72
4. Step 4: Simplify right side
   20,870.43x = 306,267,010.80
5. Step 5: Solve for x
   x = 306,267,010.80/20,870.43
6. Step 6: Final answer
   x = 14,674.69