Finding the Third Proportional to 321,777 and 423,139.50

Step by Step Solution

1. Step 1: Write the proportion equation
   321,777 : 423,139.50 = 423,139.50 : x
2. Step 2: Convert to fraction form
   321,777/423,139.50 = 423,139.50/x
3. Step 3: Cross multiply
   321,777x = 423,139.50 × 423,139.50
4. Step 4: Simplify right side
   321,777x = 179,047,036,460.25
5. Step 5: Solve for x
   x = 179,047,036,460.25/321,777
6. Step 6: Final answer
   x = 556,432.05