Finding the Third Proportional to 259,905 and 391,777.50

Step by Step Solution

1. Step 1: Write the proportion equation
   259,905 : 391,777.50 = 391,777.50 : x
2. Step 2: Convert to fraction form
   259,905/391,777.50 = 391,777.50/x
3. Step 3: Cross multiply
   259,905x = 391,777.50 × 391,777.50
4. Step 4: Simplify right side
   259,905x = 153,489,609,506.25
5. Step 5: Solve for x
   x = 153,489,609,506.25/259,905
6. Step 6: Final answer
   x = 590,560.43