Finding the Fourth Proportional to 1,638.88, 2,459.94 and 1,111.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,638.88 : 2,459.94 = 1,111.72 : x
2. Step 2: Convert to fraction form
   1,638.88/2,459.94 = 1,111.72/x
3. Step 3: Cross multiply
   1,638.88x = 2,459.94 × 1,111.72
4. Step 4: Simplify right side
   1,638.88x = 2,734,764.50
5. Step 5: Solve for x
   x = 2,734,764.50/1,638.88
6. Step 6: Final answer
   x = 1,668.68