Finding the Third Proportional to 13,780 and 21,390

Step by Step Solution

1. Step 1: Write the proportion equation
   13,780 : 21,390 = 21,390 : x
2. Step 2: Convert to fraction form
   13,780/21,390 = 21,390/x
3. Step 3: Cross multiply
   13,780x = 21,390 × 21,390
4. Step 4: Simplify right side
   13,780x = 457,532,100
5. Step 5: Solve for x
   x = 457,532,100/13,780
6. Step 6: Final answer
   x = 33,202.62