Finding the Third Proportional to 280.50 and 619.50

Step by Step Solution

1. Step 1: Write the proportion equation
   280.50 : 619.50 = 619.50 : x
2. Step 2: Convert to fraction form
   280.50/619.50 = 619.50/x
3. Step 3: Cross multiply
   280.50x = 619.50 × 619.50
4. Step 4: Simplify right side
   280.50x = 383,780.25
5. Step 5: Solve for x
   x = 383,780.25/280.50
6. Step 6: Final answer
   x = 1,368.20