Finding the Third Proportional to 2,780 and 4,290

Step by Step Solution

1. Step 1: Write the proportion equation
   2,780 : 4,290 = 4,290 : x
2. Step 2: Convert to fraction form
   2,780/4,290 = 4,290/x
3. Step 3: Cross multiply
   2,780x = 4,290 × 4,290
4. Step 4: Simplify right side
   2,780x = 18,404,100
5. Step 5: Solve for x
   x = 18,404,100/2,780
6. Step 6: Final answer
   x = 6,620.18