Finding the Third Proportional to 387,391 and 839,123

Step by Step Solution

1. Step 1: Write the proportion equation
   387,391 : 839,123 = 839,123 : x
2. Step 2: Convert to fraction form
   387,391/839,123 = 839,123/x
3. Step 3: Cross multiply
   387,391x = 839,123 × 839,123
4. Step 4: Simplify right side
   387,391x = 704,127,409,129
5. Step 5: Solve for x
   x = 704,127,409,129/387,391
6. Step 6: Final answer
   x = 1,817,614.27