Finding the Third Proportional to 259.88 and 561.38

Step by Step Solution

1. Step 1: Write the proportion equation
   259.88 : 561.38 = 561.38 : x
2. Step 2: Convert to fraction form
   259.88/561.38 = 561.38/x
3. Step 3: Cross multiply
   259.88x = 561.38 × 561.38
4. Step 4: Simplify right side
   259.88x = 315,141.89
5. Step 5: Solve for x
   x = 315,141.89/259.88
6. Step 6: Final answer
   x = 1,212.67