Finding the Third Proportional to 30,620 and 64,880

Step by Step Solution

1. Step 1: Write the proportion equation
   30,620 : 64,880 = 64,880 : x
2. Step 2: Convert to fraction form
   30,620/64,880 = 64,880/x
3. Step 3: Cross multiply
   30,620x = 64,880 × 64,880
4. Step 4: Simplify right side
   30,620x = 4,209,414,400
5. Step 5: Solve for x
   x = 4,209,414,400/30,620
6. Step 6: Final answer
   x = 137,472.71