Finding the Third Proportional to 865.13 and 1,054.69

Step by Step Solution

1. Step 1: Write the proportion equation
   865.13 : 1,054.69 = 1,054.69 : x
2. Step 2: Convert to fraction form
   865.13/1,054.69 = 1,054.69/x
3. Step 3: Cross multiply
   865.13x = 1,054.69 × 1,054.69
4. Step 4: Simplify right side
   865.13x = 1,112,365.72
5. Step 5: Solve for x
   x = 1,112,365.72/865.13
6. Step 6: Final answer
   x = 1,285.79