Finding the Third Proportional to 213,570 and 287,698.50

Step by Step Solution

1. Step 1: Write the proportion equation
   213,570 : 287,698.50 = 287,698.50 : x
2. Step 2: Convert to fraction form
   213,570/287,698.50 = 287,698.50/x
3. Step 3: Cross multiply
   213,570x = 287,698.50 × 287,698.50
4. Step 4: Simplify right side
   213,570x = 82,770,426,902.25
5. Step 5: Solve for x
   x = 82,770,426,902.25/213,570
6. Step 6: Final answer
   x = 387,556.43