Finding the Fourth Proportional to 1,426.89, 2,128.66 and 1,387.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,426.89 : 2,128.66 = 1,387.20 : x
2. Step 2: Convert to fraction form
   1,426.89/2,128.66 = 1,387.20/x
3. Step 3: Cross multiply
   1,426.89x = 2,128.66 × 1,387.20
4. Step 4: Simplify right side
   1,426.89x = 2,952,877.15
5. Step 5: Solve for x
   x = 2,952,877.15/1,426.89
6. Step 6: Final answer
   x = 2,069.45