Finding the Fourth Proportional to 1,661.79, 2,498.16 and 1,388.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,661.79 : 2,498.16 = 1,388.42 : x
2. Step 2: Convert to fraction form
   1,661.79/2,498.16 = 1,388.42/x
3. Step 3: Cross multiply
   1,661.79x = 2,498.16 × 1,388.42
4. Step 4: Simplify right side
   1,661.79x = 3,468,482.82
5. Step 5: Solve for x
   x = 3,468,482.82/1,661.79
6. Step 6: Final answer
   x = 2,087.20