Home / 4.21-6.39

Finding the Third Proportional to 4.21 and 6.39

Calculator

Solution

The third proportional to 4.21 and 6.39 is: 9.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    4.21 : 6.39 = 6.39 : x
  2. Step 2: Convert to fraction form
    4.21/6.39 = 6.39/x
  3. Step 3: Cross multiply
    4.21x = 6.39 × 6.39
  4. Step 4: Simplify right side
    4.21x = 40.87
  5. Step 5: Solve for x
    x = 40.87/4.21
  6. Step 6: Final answer
    x = 9.71

Related Problems

Find third proportional to 2.11 and 3.20
Half scale
Find third proportional to 8.42 and 12.79
Double scale
Find third proportional to 6 and 9
Similar ratio
Find third proportional to 6.32 and 9.59
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.52) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.