Finding the Third Proportional to 300,840 and 643,152

Step by Step Solution

1. Step 1: Write the proportion equation
   300,840 : 643,152 = 643,152 : x
2. Step 2: Convert to fraction form
   300,840/643,152 = 643,152/x
3. Step 3: Cross multiply
   300,840x = 643,152 × 643,152
4. Step 4: Simplify right side
   300,840x = 413,644,495,104
5. Step 5: Solve for x
   x = 413,644,495,104/300,840
6. Step 6: Final answer
   x = 1,374,965.08