Finding the Third Proportional to 171,988 and 258,990

Step by Step Solution

1. Step 1: Write the proportion equation
   171,988 : 258,990 = 258,990 : x
2. Step 2: Convert to fraction form
   171,988/258,990 = 258,990/x
3. Step 3: Cross multiply
   171,988x = 258,990 × 258,990
4. Step 4: Simplify right side
   171,988x = 67,075,820,100
5. Step 5: Solve for x
   x = 67,075,820,100/171,988
6. Step 6: Final answer
   x = 390,002.91