Finding the Third Proportional to 123,985.69 and 258,698.81

Step by Step Solution

1. Step 1: Write the proportion equation
   123,985.69 : 258,698.81 = 258,698.81 : x
2. Step 2: Convert to fraction form
   123,985.69/258,698.81 = 258,698.81/x
3. Step 3: Cross multiply
   123,985.69x = 258,698.81 × 258,698.81
4. Step 4: Simplify right side
   123,985.69x = 66,925,075,588.91
5. Step 5: Solve for x
   x = 66,925,075,588.91/123,985.69
6. Step 6: Final answer
   x = 539,780.65