Finding the Third Proportional to 289.50 and 445.31

Step by Step Solution

1. Step 1: Write the proportion equation
   289.50 : 445.31 = 445.31 : x
2. Step 2: Convert to fraction form
   289.50/445.31 = 445.31/x
3. Step 3: Cross multiply
   289.50x = 445.31 × 445.31
4. Step 4: Simplify right side
   289.50x = 198,303.22
5. Step 5: Solve for x
   x = 198,303.22/289.50
6. Step 6: Final answer
   x = 684.99