Finding the Third Proportional to 145,918.50 and 317,391

Step by Step Solution

1. Step 1: Write the proportion equation
   145,918.50 : 317,391 = 317,391 : x
2. Step 2: Convert to fraction form
   145,918.50/317,391 = 317,391/x
3. Step 3: Cross multiply
   145,918.50x = 317,391 × 317,391
4. Step 4: Simplify right side
   145,918.50x = 100,737,046,881
5. Step 5: Solve for x
   x = 100,737,046,881/145,918.50
6. Step 6: Final answer
   x = 690,365.15