Finding the Third Proportional to 261,319.50 and 390,960

Step by Step Solution

1. Step 1: Write the proportion equation
   261,319.50 : 390,960 = 390,960 : x
2. Step 2: Convert to fraction form
   261,319.50/390,960 = 390,960/x
3. Step 3: Cross multiply
   261,319.50x = 390,960 × 390,960
4. Step 4: Simplify right side
   261,319.50x = 152,849,721,600
5. Step 5: Solve for x
   x = 152,849,721,600/261,319.50
6. Step 6: Final answer
   x = 584,915.10