Finding the Fourth Proportional to 2,763.72, 4,144.86 and 815.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,763.72 : 4,144.86 = 815.40 : x
2. Step 2: Convert to fraction form
   2,763.72/4,144.86 = 815.40/x
3. Step 3: Cross multiply
   2,763.72x = 4,144.86 × 815.40
4. Step 4: Simplify right side
   2,763.72x = 3,379,718.84
5. Step 5: Solve for x
   x = 3,379,718.84/2,763.72
6. Step 6: Final answer
   x = 1,222.89