Finding the Fourth Proportional to 1,399.03, 2,115.10 and 1,387.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.03 : 2,115.10 = 1,387.51 : x
2. Step 2: Convert to fraction form
   1,399.03/2,115.10 = 1,387.51/x
3. Step 3: Cross multiply
   1,399.03x = 2,115.10 × 1,387.51
4. Step 4: Simplify right side
   1,399.03x = 2,934,704.89
5. Step 5: Solve for x
   x = 2,934,704.89/1,399.03
6. Step 6: Final answer
   x = 2,097.68