Finding the Fourth Proportional to 12,756.76, 17,604.69 and 7,721.89

Step by Step Solution

1. Step 1: Write the proportion equation
   12,756.76 : 17,604.69 = 7,721.89 : x
2. Step 2: Convert to fraction form
   12,756.76/17,604.69 = 7,721.89/x
3. Step 3: Cross multiply
   12,756.76x = 17,604.69 × 7,721.89
4. Step 4: Simplify right side
   12,756.76x = 135,941,406.70
5. Step 5: Solve for x
   x = 135,941,406.70/12,756.76
6. Step 6: Final answer
   x = 10,656.42