Finding the Third Proportional to 279,729 and 421,915.50

Step by Step Solution

1. Step 1: Write the proportion equation
   279,729 : 421,915.50 = 421,915.50 : x
2. Step 2: Convert to fraction form
   279,729/421,915.50 = 421,915.50/x
3. Step 3: Cross multiply
   279,729x = 421,915.50 × 421,915.50
4. Step 4: Simplify right side
   279,729x = 178,012,689,140.25
5. Step 5: Solve for x
   x = 178,012,689,140.25/279,729
6. Step 6: Final answer
   x = 636,375.52