Finding the Fourth Proportional to 1,387.36, 2,079.69 and 1,127.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.36 : 2,079.69 = 1,127.89 : x
2. Step 2: Convert to fraction form
   1,387.36/2,079.69 = 1,127.89/x
3. Step 3: Cross multiply
   1,387.36x = 2,079.69 × 1,127.89
4. Step 4: Simplify right side
   1,387.36x = 2,345,661.55
5. Step 5: Solve for x
   x = 2,345,661.55/1,387.36
6. Step 6: Final answer
   x = 1,690.74