Finding the Third Proportional to 390,456 and 791,777.25

Step by Step Solution

1. Step 1: Write the proportion equation
   390,456 : 791,777.25 = 791,777.25 : x
2. Step 2: Convert to fraction form
   390,456/791,777.25 = 791,777.25/x
3. Step 3: Cross multiply
   390,456x = 791,777.25 × 791,777.25
4. Step 4: Simplify right side
   390,456x = 626,911,213,617.56
5. Step 5: Solve for x
   x = 626,911,213,617.56/390,456
6. Step 6: Final answer
   x = 1,605,587.35