Finding the Third Proportional to 211.25 and 439.31

Step by Step Solution

1. Step 1: Write the proportion equation
   211.25 : 439.31 = 439.31 : x
2. Step 2: Convert to fraction form
   211.25/439.31 = 439.31/x
3. Step 3: Cross multiply
   211.25x = 439.31 × 439.31
4. Step 4: Simplify right side
   211.25x = 192,995.47
5. Step 5: Solve for x
   x = 192,995.47/211.25
6. Step 6: Final answer
   x = 913.59