Finding the Third Proportional to 561 and 1,264.50

Step by Step Solution

1. Step 1: Write the proportion equation
   561 : 1,264.50 = 1,264.50 : x
2. Step 2: Convert to fraction form
   561/1,264.50 = 1,264.50/x
3. Step 3: Cross multiply
   561x = 1,264.50 × 1,264.50
4. Step 4: Simplify right side
   561x = 1,598,960.25
5. Step 5: Solve for x
   x = 1,598,960.25/561
6. Step 6: Final answer
   x = 2,850.20