Finding the Fourth Proportional to 10,518.79, 15,775.47 and 3,121.57

Step by Step Solution

1. Step 1: Write the proportion equation
   10,518.79 : 15,775.47 = 3,121.57 : x
2. Step 2: Convert to fraction form
   10,518.79/15,775.47 = 3,121.57/x
3. Step 3: Cross multiply
   10,518.79x = 15,775.47 × 3,121.57
4. Step 4: Simplify right side
   10,518.79x = 49,244,233.89
5. Step 5: Solve for x
   x = 49,244,233.89/10,518.79
6. Step 6: Final answer
   x = 4,681.55