Home / 619-721

Finding the Third Proportional to 619 and 721

Calculator

Solution

The third proportional to 619 and 721 is: 839.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    619 : 721 = 721 : x
  2. Step 2: Convert to fraction form
    619/721 = 721/x
  3. Step 3: Cross multiply
    619x = 721 × 721
  4. Step 4: Simplify right side
    619x = 519,841
  5. Step 5: Solve for x
    x = 519,841/619
  6. Step 6: Final answer
    x = 839.81

Related Problems

Find third proportional to 309.50 and 360.50
Half scale
Find third proportional to 1,238 and 1,442
Double scale
Find third proportional to 621 and 723
Similar ratio
Find third proportional to 928.50 and 1,081.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.16) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.