Finding the Third Proportional to 639,258 and 1,378,147.50

Step by Step Solution

1. Step 1: Write the proportion equation
   639,258 : 1,378,147.50 = 1,378,147.50 : x
2. Step 2: Convert to fraction form
   639,258/1,378,147.50 = 1,378,147.50/x
3. Step 3: Cross multiply
   639,258x = 1,378,147.50 × 1,378,147.50
4. Step 4: Simplify right side
   639,258x = 1,899,290,531,756.25
5. Step 5: Solve for x
   x = 1,899,290,531,756.25/639,258
6. Step 6: Final answer
   x = 2,971,086.06