Finding the Third Proportional to 261,144 and 390,726

Step by Step Solution

1. Step 1: Write the proportion equation
   261,144 : 390,726 = 390,726 : x
2. Step 2: Convert to fraction form
   261,144/390,726 = 390,726/x
3. Step 3: Cross multiply
   261,144x = 390,726 × 390,726
4. Step 4: Simplify right side
   261,144x = 152,666,807,076
5. Step 5: Solve for x
   x = 152,666,807,076/261,144
6. Step 6: Final answer
   x = 584,607.75