Finding the Fourth Proportional to 2,820.06, 3,891.76 and 1,561.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,820.06 : 3,891.76 = 1,561.20 : x
2. Step 2: Convert to fraction form
   2,820.06/3,891.76 = 1,561.20/x
3. Step 3: Cross multiply
   2,820.06x = 3,891.76 × 1,561.20
4. Step 4: Simplify right side
   2,820.06x = 6,075,815.71
5. Step 5: Solve for x
   x = 6,075,815.71/2,820.06
6. Step 6: Final answer
   x = 2,154.50