Finding the Third Proportional to 321,056 and 691,781.50

Step by Step Solution

1. Step 1: Write the proportion equation
   321,056 : 691,781.50 = 691,781.50 : x
2. Step 2: Convert to fraction form
   321,056/691,781.50 = 691,781.50/x
3. Step 3: Cross multiply
   321,056x = 691,781.50 × 691,781.50
4. Step 4: Simplify right side
   321,056x = 478,561,643,742.25
5. Step 5: Solve for x
   x = 478,561,643,742.25/321,056
6. Step 6: Final answer
   x = 1,490,586.20