Finding the Third Proportional to 285,919 and 420,559.50

Step by Step Solution

1. Step 1: Write the proportion equation
   285,919 : 420,559.50 = 420,559.50 : x
2. Step 2: Convert to fraction form
   285,919/420,559.50 = 420,559.50/x
3. Step 3: Cross multiply
   285,919x = 420,559.50 × 420,559.50
4. Step 4: Simplify right side
   285,919x = 176,870,293,040.25
5. Step 5: Solve for x
   x = 176,870,293,040.25/285,919
6. Step 6: Final answer
   x = 618,602.80