Finding the Third Proportional to 2,688.19 and 3,986.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,688.19 : 3,986.72 = 3,986.72 : x
2. Step 2: Convert to fraction form
   2,688.19/3,986.72 = 3,986.72/x
3. Step 3: Cross multiply
   2,688.19x = 3,986.72 × 3,986.72
4. Step 4: Simplify right side
   2,688.19x = 15,893,926.39
5. Step 5: Solve for x
   x = 15,893,926.39/2,688.19
6. Step 6: Final answer
   x = 5,912.51