Finding the Third Proportional to 3,985.29 and 8,402.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,985.29 : 8,402.72 = 8,402.72 : x
2. Step 2: Convert to fraction form
   3,985.29/8,402.72 = 8,402.72/x
3. Step 3: Cross multiply
   3,985.29x = 8,402.72 × 8,402.72
4. Step 4: Simplify right side
   3,985.29x = 70,605,731.63
5. Step 5: Solve for x
   x = 70,605,731.63/3,985.29
6. Step 6: Final answer
   x = 17,716.56