Finding the Third Proportional to 218,709 and 342,643.50

Step by Step Solution

1. Step 1: Write the proportion equation
   218,709 : 342,643.50 = 342,643.50 : x
2. Step 2: Convert to fraction form
   218,709/342,643.50 = 342,643.50/x
3. Step 3: Cross multiply
   218,709x = 342,643.50 × 342,643.50
4. Step 4: Simplify right side
   218,709x = 117,404,568,092.25
5. Step 5: Solve for x
   x = 117,404,568,092.25/218,709
6. Step 6: Final answer
   x = 536,807.21