Finding the Third Proportional to 191,917 and 405,978

Step by Step Solution

1. Step 1: Write the proportion equation
   191,917 : 405,978 = 405,978 : x
2. Step 2: Convert to fraction form
   191,917/405,978 = 405,978/x
3. Step 3: Cross multiply
   191,917x = 405,978 × 405,978
4. Step 4: Simplify right side
   191,917x = 164,818,136,484
5. Step 5: Solve for x
   x = 164,818,136,484/191,917
6. Step 6: Final answer
   x = 858,799.05