Finding the Third Proportional to 287,721 and 435,579.50

Step by Step Solution

1. Step 1: Write the proportion equation
   287,721 : 435,579.50 = 435,579.50 : x
2. Step 2: Convert to fraction form
   287,721/435,579.50 = 435,579.50/x
3. Step 3: Cross multiply
   287,721x = 435,579.50 × 435,579.50
4. Step 4: Simplify right side
   287,721x = 189,729,500,820.25
5. Step 5: Solve for x
   x = 189,729,500,820.25/287,721
6. Step 6: Final answer
   x = 659,421.80