Finding the Fourth Proportional to 2,128.98, 2,938.05 and 1,289.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.98 : 2,938.05 = 1,289.55 : x
2. Step 2: Convert to fraction form
   2,128.98/2,938.05 = 1,289.55/x
3. Step 3: Cross multiply
   2,128.98x = 2,938.05 × 1,289.55
4. Step 4: Simplify right side
   2,128.98x = 3,788,762.38
5. Step 5: Solve for x
   x = 3,788,762.38/2,128.98
6. Step 6: Final answer
   x = 1,779.61