Finding the Third Proportional to 139,426 and 210,438

Step by Step Solution

1. Step 1: Write the proportion equation
   139,426 : 210,438 = 210,438 : x
2. Step 2: Convert to fraction form
   139,426/210,438 = 210,438/x
3. Step 3: Cross multiply
   139,426x = 210,438 × 210,438
4. Step 4: Simplify right side
   139,426x = 44,284,151,844
5. Step 5: Solve for x
   x = 44,284,151,844/139,426
6. Step 6: Final answer
   x = 317,617.60