Home / 81-189

Finding the Third Proportional to 81 and 189

Calculator

Solution

The third proportional to 81 and 189 is: 441

Step by Step Solution

  1. Step 1: Write the proportion equation
    81 : 189 = 189 : x
  2. Step 2: Convert to fraction form
    81/189 = 189/x
  3. Step 3: Cross multiply
    81x = 189 × 189
  4. Step 4: Simplify right side
    81x = 35,721
  5. Step 5: Solve for x
    x = 35,721/81
  6. Step 6: Final answer
    x = 441

Related Problems

Find third proportional to 40.50 and 94.50
Half scale
Find third proportional to 162 and 378
Double scale
Find third proportional to 83 and 194
Similar ratio
Find third proportional to 121.50 and 283.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.