Home / 67-78

Finding the Third Proportional to 67 and 78

Calculator

Solution

The third proportional to 67 and 78 is: 90.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    67 : 78 = 78 : x
  2. Step 2: Convert to fraction form
    67/78 = 78/x
  3. Step 3: Cross multiply
    67x = 78 × 78
  4. Step 4: Simplify right side
    67x = 6,084
  5. Step 5: Solve for x
    x = 6,084/67
  6. Step 6: Final answer
    x = 90.81

Related Problems

Find third proportional to 33.50 and 39
Half scale
Find third proportional to 134 and 156
Double scale
Find third proportional to 69 and 80
Similar ratio
Find third proportional to 100.50 and 117
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.16) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.