Finding the Third Proportional to 860.50 and 1,285.50

Step by Step Solution

1. Step 1: Write the proportion equation
   860.50 : 1,285.50 = 1,285.50 : x
2. Step 2: Convert to fraction form
   860.50/1,285.50 = 1,285.50/x
3. Step 3: Cross multiply
   860.50x = 1,285.50 × 1,285.50
4. Step 4: Simplify right side
   860.50x = 1,652,510.25
5. Step 5: Solve for x
   x = 1,652,510.25/860.50
6. Step 6: Final answer
   x = 1,920.41