Finding the Third Proportional to 166,636 and 258,090

Step by Step Solution

1. Step 1: Write the proportion equation
   166,636 : 258,090 = 258,090 : x
2. Step 2: Convert to fraction form
   166,636/258,090 = 258,090/x
3. Step 3: Cross multiply
   166,636x = 258,090 × 258,090
4. Step 4: Simplify right side
   166,636x = 66,610,448,100
5. Step 5: Solve for x
   x = 66,610,448,100/166,636
6. Step 6: Final answer
   x = 399,736.24