Finding the Third Proportional to 64,990 and 142,392

Step by Step Solution

1. Step 1: Write the proportion equation
   64,990 : 142,392 = 142,392 : x
2. Step 2: Convert to fraction form
   64,990/142,392 = 142,392/x
3. Step 3: Cross multiply
   64,990x = 142,392 × 142,392
4. Step 4: Simplify right side
   64,990x = 20,275,481,664
5. Step 5: Solve for x
   x = 20,275,481,664/64,990
6. Step 6: Final answer
   x = 311,978.48