Finding the Third Proportional to 209,430 and 280,921.50

Step by Step Solution

1. Step 1: Write the proportion equation
   209,430 : 280,921.50 = 280,921.50 : x
2. Step 2: Convert to fraction form
   209,430/280,921.50 = 280,921.50/x
3. Step 3: Cross multiply
   209,430x = 280,921.50 × 280,921.50
4. Step 4: Simplify right side
   209,430x = 78,916,889,162.25
5. Step 5: Solve for x
   x = 78,916,889,162.25/209,430
6. Step 6: Final answer
   x = 376,817.50