Finding the Third Proportional to 858.38 and 1,386.56

Step by Step Solution

1. Step 1: Write the proportion equation
   858.38 : 1,386.56 = 1,386.56 : x
2. Step 2: Convert to fraction form
   858.38/1,386.56 = 1,386.56/x
3. Step 3: Cross multiply
   858.38x = 1,386.56 × 1,386.56
4. Step 4: Simplify right side
   858.38x = 1,922,555.57
5. Step 5: Solve for x
   x = 1,922,555.57/858.38
6. Step 6: Final answer
   x = 2,239.76