Finding the Third Proportional to 149,890.50 and 321,148.50

Step by Step Solution

1. Step 1: Write the proportion equation
   149,890.50 : 321,148.50 = 321,148.50 : x
2. Step 2: Convert to fraction form
   149,890.50/321,148.50 = 321,148.50/x
3. Step 3: Cross multiply
   149,890.50x = 321,148.50 × 321,148.50
4. Step 4: Simplify right side
   149,890.50x = 103,136,359,052.25
5. Step 5: Solve for x
   x = 103,136,359,052.25/149,890.50
6. Step 6: Final answer
   x = 688,078.02