Finding the Fourth Proportional to 2,085.28, 2,877.20 and 1,200.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.28 : 2,877.20 = 1,200.80 : x
2. Step 2: Convert to fraction form
   2,085.28/2,877.20 = 1,200.80/x
3. Step 3: Cross multiply
   2,085.28x = 2,877.20 × 1,200.80
4. Step 4: Simplify right side
   2,085.28x = 3,454,941.76
5. Step 5: Solve for x
   x = 3,454,941.76/2,085.28
6. Step 6: Final answer
   x = 1,656.82