Finding the Third Proportional to 859.78 and 1,320.89

Step by Step Solution

1. Step 1: Write the proportion equation
   859.78 : 1,320.89 = 1,320.89 : x
2. Step 2: Convert to fraction form
   859.78/1,320.89 = 1,320.89/x
3. Step 3: Cross multiply
   859.78x = 1,320.89 × 1,320.89
4. Step 4: Simplify right side
   859.78x = 1,744,752.04
5. Step 5: Solve for x
   x = 1,744,752.04/859.78
6. Step 6: Final answer
   x = 2,029.30