Finding the Third Proportional to 259.94 and 389.69

Step by Step Solution

1. Step 1: Write the proportion equation
   259.94 : 389.69 = 389.69 : x
2. Step 2: Convert to fraction form
   259.94/389.69 = 389.69/x
3. Step 3: Cross multiply
   259.94x = 389.69 × 389.69
4. Step 4: Simplify right side
   259.94x = 151,856.35
5. Step 5: Solve for x
   x = 151,856.35/259.94
6. Step 6: Final answer
   x = 584.20