Finding the Third Proportional to 398.53 and 538.31

Step by Step Solution

1. Step 1: Write the proportion equation
   398.53 : 538.31 = 538.31 : x
2. Step 2: Convert to fraction form
   398.53/538.31 = 538.31/x
3. Step 3: Cross multiply
   398.53x = 538.31 × 538.31
4. Step 4: Simplify right side
   398.53x = 289,780.35
5. Step 5: Solve for x
   x = 289,780.35/398.53
6. Step 6: Final answer
   x = 727.12