Finding the Third Proportional to 9,978.19 and 10,828.69

Step by Step Solution

1. Step 1: Write the proportion equation
   9,978.19 : 10,828.69 = 10,828.69 : x
2. Step 2: Convert to fraction form
   9,978.19/10,828.69 = 10,828.69/x
3. Step 3: Cross multiply
   9,978.19x = 10,828.69 × 10,828.69
4. Step 4: Simplify right side
   9,978.19x = 117,260,472.97
5. Step 5: Solve for x
   x = 117,260,472.97/9,978.19
6. Step 6: Final answer
   x = 11,751.68