Finding the Third Proportional to 1,620 and 1,890

Step by Step Solution

1. Step 1: Write the proportion equation
   1,620 : 1,890 = 1,890 : x
2. Step 2: Convert to fraction form
   1,620/1,890 = 1,890/x
3. Step 3: Cross multiply
   1,620x = 1,890 × 1,890
4. Step 4: Simplify right side
   1,620x = 3,572,100
5. Step 5: Solve for x
   x = 3,572,100/1,620
6. Step 6: Final answer
   x = 2,205