Finding the Third Proportional to 275.91 and 580.78

Step by Step Solution

1. Step 1: Write the proportion equation
   275.91 : 580.78 = 580.78 : x
2. Step 2: Convert to fraction form
   275.91/580.78 = 580.78/x
3. Step 3: Cross multiply
   275.91x = 580.78 × 580.78
4. Step 4: Simplify right side
   275.91x = 337,306.86
5. Step 5: Solve for x
   x = 337,306.86/275.91
6. Step 6: Final answer
   x = 1,222.54