Finding the Third Proportional to 864 and 1,270.69

Step by Step Solution

1. Step 1: Write the proportion equation
   864 : 1,270.69 = 1,270.69 : x
2. Step 2: Convert to fraction form
   864/1,270.69 = 1,270.69/x
3. Step 3: Cross multiply
   864x = 1,270.69 × 1,270.69
4. Step 4: Simplify right side
   864x = 1,614,646.72
5. Step 5: Solve for x
   x = 1,614,646.72/864
6. Step 6: Final answer
   x = 1,868.80