Home / 11.25-21

Finding the Third Proportional to 11.25 and 21

Calculator

Solution

The third proportional to 11.25 and 21 is: 39.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.25 : 21 = 21 : x
  2. Step 2: Convert to fraction form
    11.25/21 = 21/x
  3. Step 3: Cross multiply
    11.25x = 21 × 21
  4. Step 4: Simplify right side
    11.25x = 441
  5. Step 5: Solve for x
    x = 441/11.25
  6. Step 6: Final answer
    x = 39.20

Related Problems

Find third proportional to 5.63 and 10.50
Half scale
Find third proportional to 22.50 and 42
Double scale
Find third proportional to 13 and 25
Similar ratio
Find third proportional to 16.88 and 31.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.87) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.