Finding the Fourth Proportional to 1,989.85, 2,743.72 and 1,428.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,989.85 : 2,743.72 = 1,428.52 : x
2. Step 2: Convert to fraction form
   1,989.85/2,743.72 = 1,428.52/x
3. Step 3: Cross multiply
   1,989.85x = 2,743.72 × 1,428.52
4. Step 4: Simplify right side
   1,989.85x = 3,919,458.89
5. Step 5: Solve for x
   x = 3,919,458.89/1,989.85
6. Step 6: Final answer
   x = 1,969.73