Finding the Third Proportional to 121.71 and 260.72

Step by Step Solution

1. Step 1: Write the proportion equation
   121.71 : 260.72 = 260.72 : x
2. Step 2: Convert to fraction form
   121.71/260.72 = 260.72/x
3. Step 3: Cross multiply
   121.71x = 260.72 × 260.72
4. Step 4: Simplify right side
   121.71x = 67,974.27
5. Step 5: Solve for x
   x = 67,974.27/121.71
6. Step 6: Final answer
   x = 558.49