Finding the Fourth Proportional to 1,559.48, 2,151.41 and 999.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,559.48 : 2,151.41 = 999.77 : x
2. Step 2: Convert to fraction form
   1,559.48/2,151.41 = 999.77/x
3. Step 3: Cross multiply
   1,559.48x = 2,151.41 × 999.77
4. Step 4: Simplify right side
   1,559.48x = 2,150,899.42
5. Step 5: Solve for x
   x = 2,150,899.42/1,559.48
6. Step 6: Final answer
   x = 1,379.25