Finding the Fourth Proportional to 1,407.28, 1,939.70 and 1,289.62

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.28 : 1,939.70 = 1,289.62 : x
2. Step 2: Convert to fraction form
   1,407.28/1,939.70 = 1,289.62/x
3. Step 3: Cross multiply
   1,407.28x = 1,939.70 × 1,289.62
4. Step 4: Simplify right side
   1,407.28x = 2,501,475.91
5. Step 5: Solve for x
   x = 2,501,475.91/1,407.28
6. Step 6: Final answer
   x = 1,777.53