Finding the Third Proportional to 1,387.69 and 2,140.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,387.69 : 2,140.31 = 2,140.31 : x
2. Step 2: Convert to fraction form
   1,387.69/2,140.31 = 2,140.31/x
3. Step 3: Cross multiply
   1,387.69x = 2,140.31 × 2,140.31
4. Step 4: Simplify right side
   1,387.69x = 4,580,937.60
5. Step 5: Solve for x
   x = 4,580,937.60/1,387.69
6. Step 6: Final answer
   x = 3,301.13