Finding the Fourth Proportional to 2,587.72, 3,879.96 and 1,200.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,587.72 : 3,879.96 = 1,200.20 : x
2. Step 2: Convert to fraction form
   2,587.72/3,879.96 = 1,200.20/x
3. Step 3: Cross multiply
   2,587.72x = 3,879.96 × 1,200.20
4. Step 4: Simplify right side
   2,587.72x = 4,656,727.99
5. Step 5: Solve for x
   x = 4,656,727.99/2,587.72
6. Step 6: Final answer
   x = 1,799.55