Home / 1,209-1,605

Finding the Third Proportional to 1,209 and 1,605

Calculator

Solution

The third proportional to 1,209 and 1,605 is: 2,130.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209 : 1,605 = 1,605 : x
  2. Step 2: Convert to fraction form
    1,209/1,605 = 1,605/x
  3. Step 3: Cross multiply
    1,209x = 1,605 × 1,605
  4. Step 4: Simplify right side
    1,209x = 2,576,025
  5. Step 5: Solve for x
    x = 2,576,025/1,209
  6. Step 6: Final answer
    x = 2,130.71

Related Problems

Find third proportional to 604.50 and 802.50
Half scale
Find third proportional to 2,418 and 3,210
Double scale
Find third proportional to 1,211 and 1,608
Similar ratio
Find third proportional to 1,813.50 and 2,407.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.