Finding the Third Proportional to 209,559.50 and 428,802.50

Step by Step Solution

1. Step 1: Write the proportion equation
   209,559.50 : 428,802.50 = 428,802.50 : x
2. Step 2: Convert to fraction form
   209,559.50/428,802.50 = 428,802.50/x
3. Step 3: Cross multiply
   209,559.50x = 428,802.50 × 428,802.50
4. Step 4: Simplify right side
   209,559.50x = 183,871,584,006.25
5. Step 5: Solve for x
   x = 183,871,584,006.25/209,559.50
6. Step 6: Final answer
   x = 877,419.46