Finding the Third Proportional to 1,687.69 and 3,509.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,687.69 : 3,509.81 = 3,509.81 : x
2. Step 2: Convert to fraction form
   1,687.69/3,509.81 = 3,509.81/x
3. Step 3: Cross multiply
   1,687.69x = 3,509.81 × 3,509.81
4. Step 4: Simplify right side
   1,687.69x = 12,318,783.79
5. Step 5: Solve for x
   x = 12,318,783.79/1,687.69
6. Step 6: Final answer
   x = 7,299.21