Finding the Third Proportional to 1,285.50 and 1,420.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,285.50 : 1,420.50 = 1,420.50 : x
2. Step 2: Convert to fraction form
   1,285.50/1,420.50 = 1,420.50/x
3. Step 3: Cross multiply
   1,285.50x = 1,420.50 × 1,420.50
4. Step 4: Simplify right side
   1,285.50x = 2,017,820.25
5. Step 5: Solve for x
   x = 2,017,820.25/1,285.50
6. Step 6: Final answer
   x = 1,569.68