Home / 1,689-1,821

Finding the Third Proportional to 1,689 and 1,821

Calculator

Solution

The third proportional to 1,689 and 1,821 is: 1,963.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,689 : 1,821 = 1,821 : x
  2. Step 2: Convert to fraction form
    1,689/1,821 = 1,821/x
  3. Step 3: Cross multiply
    1,689x = 1,821 × 1,821
  4. Step 4: Simplify right side
    1,689x = 3,316,041
  5. Step 5: Solve for x
    x = 3,316,041/1,689
  6. Step 6: Final answer
    x = 1,963.32

Related Problems

Find third proportional to 844.50 and 910.50
Half scale
Find third proportional to 3,378 and 3,642
Double scale
Find third proportional to 1,691 and 1,823
Similar ratio
Find third proportional to 2,533.50 and 2,731.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.08) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.