Finding the Third Proportional to 638,740 and 1,390,880

Step by Step Solution

1. Step 1: Write the proportion equation
   638,740 : 1,390,880 = 1,390,880 : x
2. Step 2: Convert to fraction form
   638,740/1,390,880 = 1,390,880/x
3. Step 3: Cross multiply
   638,740x = 1,390,880 × 1,390,880
4. Step 4: Simplify right side
   638,740x = 1,934,547,174,400
5. Step 5: Solve for x
   x = 1,934,547,174,400/638,740
6. Step 6: Final answer
   x = 3,028,692.70