Finding the Third Proportional to 2,776 and 3,990

Step by Step Solution

1. Step 1: Write the proportion equation
   2,776 : 3,990 = 3,990 : x
2. Step 2: Convert to fraction form
   2,776/3,990 = 3,990/x
3. Step 3: Cross multiply
   2,776x = 3,990 × 3,990
4. Step 4: Simplify right side
   2,776x = 15,920,100
5. Step 5: Solve for x
   x = 15,920,100/2,776
6. Step 6: Final answer
   x = 5,734.91