Finding the Third Proportional to 9,120 and 13,821

Step by Step Solution

1. Step 1: Write the proportion equation
   9,120 : 13,821 = 13,821 : x
2. Step 2: Convert to fraction form
   9,120/13,821 = 13,821/x
3. Step 3: Cross multiply
   9,120x = 13,821 × 13,821
4. Step 4: Simplify right side
   9,120x = 191,020,041
5. Step 5: Solve for x
   x = 191,020,041/9,120
6. Step 6: Final answer
   x = 20,945.18