Finding the Fourth Proportional to 20,961.76, 31,428.72 and 8,303.12

Step by Step Solution

1. Step 1: Write the proportion equation
   20,961.76 : 31,428.72 = 8,303.12 : x
2. Step 2: Convert to fraction form
   20,961.76/31,428.72 = 8,303.12/x
3. Step 3: Cross multiply
   20,961.76x = 31,428.72 × 8,303.12
4. Step 4: Simplify right side
   20,961.76x = 260,956,433.61
5. Step 5: Solve for x
   x = 260,956,433.61/20,961.76
6. Step 6: Final answer
   x = 12,449.17