Finding the Third Proportional to 5,160 and 10,640

Step by Step Solution

1. Step 1: Write the proportion equation
   5,160 : 10,640 = 10,640 : x
2. Step 2: Convert to fraction form
   5,160/10,640 = 10,640/x
3. Step 3: Cross multiply
   5,160x = 10,640 × 10,640
4. Step 4: Simplify right side
   5,160x = 113,209,600
5. Step 5: Solve for x
   x = 113,209,600/5,160
6. Step 6: Final answer
   x = 21,939.84