Home / 80-109

Finding the Third Proportional to 80 and 109

Calculator

Solution

The third proportional to 80 and 109 is: 148.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    80 : 109 = 109 : x
  2. Step 2: Convert to fraction form
    80/109 = 109/x
  3. Step 3: Cross multiply
    80x = 109 × 109
  4. Step 4: Simplify right side
    80x = 11,881
  5. Step 5: Solve for x
    x = 11,881/80
  6. Step 6: Final answer
    x = 148.51

Related Problems

Find third proportional to 40 and 54.50
Half scale
Find third proportional to 160 and 218
Double scale
Find third proportional to 82 and 112
Similar ratio
Find third proportional to 120 and 163.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.