Finding the Third Proportional to 386,383 and 509,302.50

Step by Step Solution

1. Step 1: Write the proportion equation
   386,383 : 509,302.50 = 509,302.50 : x
2. Step 2: Convert to fraction form
   386,383/509,302.50 = 509,302.50/x
3. Step 3: Cross multiply
   386,383x = 509,302.50 × 509,302.50
4. Step 4: Simplify right side
   386,383x = 259,389,036,506.25
5. Step 5: Solve for x
   x = 259,389,036,506.25/386,383
6. Step 6: Final answer
   x = 671,326.21