Finding the Third Proportional to 64,640 and 142,240

Step by Step Solution

1. Step 1: Write the proportion equation
   64,640 : 142,240 = 142,240 : x
2. Step 2: Convert to fraction form
   64,640/142,240 = 142,240/x
3. Step 3: Cross multiply
   64,640x = 142,240 × 142,240
4. Step 4: Simplify right side
   64,640x = 20,232,217,600
5. Step 5: Solve for x
   x = 20,232,217,600/64,640
6. Step 6: Final answer
   x = 312,998.42