Finding the Third Proportional to 90,640 and 213,256

Step by Step Solution

1. Step 1: Write the proportion equation
   90,640 : 213,256 = 213,256 : x
2. Step 2: Convert to fraction form
   90,640/213,256 = 213,256/x
3. Step 3: Cross multiply
   90,640x = 213,256 × 213,256
4. Step 4: Simplify right side
   90,640x = 45,478,121,536
5. Step 5: Solve for x
   x = 45,478,121,536/90,640
6. Step 6: Final answer
   x = 501,744.50