Home / 21.06-39

Finding the Third Proportional to 21.06 and 39

Calculator

Solution

The third proportional to 21.06 and 39 is: 72.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.06 : 39 = 39 : x
  2. Step 2: Convert to fraction form
    21.06/39 = 39/x
  3. Step 3: Cross multiply
    21.06x = 39 × 39
  4. Step 4: Simplify right side
    21.06x = 1,521
  5. Step 5: Solve for x
    x = 1,521/21.06
  6. Step 6: Final answer
    x = 72.21

Related Problems

Find third proportional to 10.53 and 19.50
Half scale
Find third proportional to 42.13 and 78
Double scale
Find third proportional to 23 and 43
Similar ratio
Find third proportional to 31.59 and 58.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.85) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.