Finding the Fourth Proportional to 2,820.79, 3,892.56 and 1,561.76

Step by Step Solution

1. Step 1: Write the proportion equation
   2,820.79 : 3,892.56 = 1,561.76 : x
2. Step 2: Convert to fraction form
   2,820.79/3,892.56 = 1,561.76/x
3. Step 3: Cross multiply
   2,820.79x = 3,892.56 × 1,561.76
4. Step 4: Simplify right side
   2,820.79x = 6,079,233.78
5. Step 5: Solve for x
   x = 6,079,233.78/2,820.79
6. Step 6: Final answer
   x = 2,155.15