Finding the Third Proportional to 261,300 and 390,930

Step by Step Solution

1. Step 1: Write the proportion equation
   261,300 : 390,930 = 390,930 : x
2. Step 2: Convert to fraction form
   261,300/390,930 = 390,930/x
3. Step 3: Cross multiply
   261,300x = 390,930 × 390,930
4. Step 4: Simplify right side
   261,300x = 152,826,264,900
5. Step 5: Solve for x
   x = 152,826,264,900/261,300
6. Step 6: Final answer
   x = 584,868.98