Finding the Third Proportional to 2,490 and 5,390

Step by Step Solution

1. Step 1: Write the proportion equation
   2,490 : 5,390 = 5,390 : x
2. Step 2: Convert to fraction form
   2,490/5,390 = 5,390/x
3. Step 3: Cross multiply
   2,490x = 5,390 × 5,390
4. Step 4: Simplify right side
   2,490x = 29,052,100
5. Step 5: Solve for x
   x = 29,052,100/2,490
6. Step 6: Final answer
   x = 11,667.51