Finding the Third Proportional to 90,128 and 208,640

Step by Step Solution

1. Step 1: Write the proportion equation
   90,128 : 208,640 = 208,640 : x
2. Step 2: Convert to fraction form
   90,128/208,640 = 208,640/x
3. Step 3: Cross multiply
   90,128x = 208,640 × 208,640
4. Step 4: Simplify right side
   90,128x = 43,530,649,600
5. Step 5: Solve for x
   x = 43,530,649,600/90,128
6. Step 6: Final answer
   x = 482,986.97