Finding the Fourth Proportional to 1,661.10, 2,488.53 and 1,388.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,661.10 : 2,488.53 = 1,388.94 : x
2. Step 2: Convert to fraction form
   1,661.10/2,488.53 = 1,388.94/x
3. Step 3: Cross multiply
   1,661.10x = 2,488.53 × 1,388.94
4. Step 4: Simplify right side
   1,661.10x = 3,456,418.86
5. Step 5: Solve for x
   x = 3,456,418.86/1,661.10
6. Step 6: Final answer
   x = 2,080.80