Finding the Third Proportional to 278,685 and 387,769.50

Step by Step Solution

1. Step 1: Write the proportion equation
   278,685 : 387,769.50 = 387,769.50 : x
2. Step 2: Convert to fraction form
   278,685/387,769.50 = 387,769.50/x
3. Step 3: Cross multiply
   278,685x = 387,769.50 × 387,769.50
4. Step 4: Simplify right side
   278,685x = 150,365,185,130.25
5. Step 5: Solve for x
   x = 150,365,185,130.25/278,685
6. Step 6: Final answer
   x = 539,552.49