Finding the Fourth Proportional to 1,665.60, 2,494.60 and 1,428.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,665.60 : 2,494.60 = 1,428.67 : x
2. Step 2: Convert to fraction form
   1,665.60/2,494.60 = 1,428.67/x
3. Step 3: Cross multiply
   1,665.60x = 2,494.60 × 1,428.67
4. Step 4: Simplify right side
   1,665.60x = 3,563,959.73
5. Step 5: Solve for x
   x = 3,563,959.73/1,665.60
6. Step 6: Final answer
   x = 2,139.75