Finding the Third Proportional to 243,783 and 389,290.50

Step by Step Solution

1. Step 1: Write the proportion equation
   243,783 : 389,290.50 = 389,290.50 : x
2. Step 2: Convert to fraction form
   243,783/389,290.50 = 389,290.50/x
3. Step 3: Cross multiply
   243,783x = 389,290.50 × 389,290.50
4. Step 4: Simplify right side
   243,783x = 151,547,093,390.25
5. Step 5: Solve for x
   x = 151,547,093,390.25/243,783
6. Step 6: Final answer
   x = 621,647.50