Finding the Fourth Proportional to 1,428.84, 1,966.28 and 1,387.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.84 : 1,966.28 = 1,387.94 : x
2. Step 2: Convert to fraction form
   1,428.84/1,966.28 = 1,387.94/x
3. Step 3: Cross multiply
   1,428.84x = 1,966.28 × 1,387.94
4. Step 4: Simplify right side
   1,428.84x = 2,729,061.89
5. Step 5: Solve for x
   x = 2,729,061.89/1,428.84
6. Step 6: Final answer
   x = 1,909.98