Finding the Third Proportional to 143,407.50 and 315,109.50

Step by Step Solution

1. Step 1: Write the proportion equation
   143,407.50 : 315,109.50 = 315,109.50 : x
2. Step 2: Convert to fraction form
   143,407.50/315,109.50 = 315,109.50/x
3. Step 3: Cross multiply
   143,407.50x = 315,109.50 × 315,109.50
4. Step 4: Simplify right side
   143,407.50x = 99,293,996,990.25
5. Step 5: Solve for x
   x = 99,293,996,990.25/143,407.50
6. Step 6: Final answer
   x = 692,390.54