Finding the Third Proportional to 293,978 and 643,980

Step by Step Solution

1. Step 1: Write the proportion equation
   293,978 : 643,980 = 643,980 : x
2. Step 2: Convert to fraction form
   293,978/643,980 = 643,980/x
3. Step 3: Cross multiply
   293,978x = 643,980 × 643,980
4. Step 4: Simplify right side
   293,978x = 414,710,240,400
5. Step 5: Solve for x
   x = 414,710,240,400/293,978
6. Step 6: Final answer
   x = 1,410,684.61