Finding the Third Proportional to 99,139.50 and 206,487

Step by Step Solution

1. Step 1: Write the proportion equation
   99,139.50 : 206,487 = 206,487 : x
2. Step 2: Convert to fraction form
   99,139.50/206,487 = 206,487/x
3. Step 3: Cross multiply
   99,139.50x = 206,487 × 206,487
4. Step 4: Simplify right side
   99,139.50x = 42,636,881,169
5. Step 5: Solve for x
   x = 42,636,881,169/99,139.50
6. Step 6: Final answer
   x = 430,069.56