Finding the Third Proportional to 299,173.50 and 640,386

Step by Step Solution

1. Step 1: Write the proportion equation
   299,173.50 : 640,386 = 640,386 : x
2. Step 2: Convert to fraction form
   299,173.50/640,386 = 640,386/x
3. Step 3: Cross multiply
   299,173.50x = 640,386 × 640,386
4. Step 4: Simplify right side
   299,173.50x = 410,094,228,996
5. Step 5: Solve for x
   x = 410,094,228,996/299,173.50
6. Step 6: Final answer
   x = 1,370,757.20