Finding the Third Proportional to 428,309 and 921,209.50

Step by Step Solution

1. Step 1: Write the proportion equation
   428,309 : 921,209.50 = 921,209.50 : x
2. Step 2: Convert to fraction form
   428,309/921,209.50 = 921,209.50/x
3. Step 3: Cross multiply
   428,309x = 921,209.50 × 921,209.50
4. Step 4: Simplify right side
   428,309x = 848,626,942,890.25
5. Step 5: Solve for x
   x = 848,626,942,890.25/428,309
6. Step 6: Final answer
   x = 1,981,342.78