Finding the Third Proportional to 66,424 and 142,688

Step by Step Solution

1. Step 1: Write the proportion equation
   66,424 : 142,688 = 142,688 : x
2. Step 2: Convert to fraction form
   66,424/142,688 = 142,688/x
3. Step 3: Cross multiply
   66,424x = 142,688 × 142,688
4. Step 4: Simplify right side
   66,424x = 20,359,865,344
5. Step 5: Solve for x
   x = 20,359,865,344/66,424
6. Step 6: Final answer
   x = 306,513.69