Finding the Third Proportional to 378,685.50 and 816,420

Step by Step Solution

1. Step 1: Write the proportion equation
   378,685.50 : 816,420 = 816,420 : x
2. Step 2: Convert to fraction form
   378,685.50/816,420 = 816,420/x
3. Step 3: Cross multiply
   378,685.50x = 816,420 × 816,420
4. Step 4: Simplify right side
   378,685.50x = 666,541,616,400
5. Step 5: Solve for x
   x = 666,541,616,400/378,685.50
6. Step 6: Final answer
   x = 1,760,145.60