Finding the Third Proportional to 5,451.50 and 8,390.50

Step by Step Solution

1. Step 1: Write the proportion equation
   5,451.50 : 8,390.50 = 8,390.50 : x
2. Step 2: Convert to fraction form
   5,451.50/8,390.50 = 8,390.50/x
3. Step 3: Cross multiply
   5,451.50x = 8,390.50 × 8,390.50
4. Step 4: Simplify right side
   5,451.50x = 70,400,490.25
5. Step 5: Solve for x
   x = 70,400,490.25/5,451.50
6. Step 6: Final answer
   x = 12,913.97