Home / 42-55

Finding the Third Proportional to 42 and 55

Calculator

Solution

The third proportional to 42 and 55 is: 72.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    42 : 55 = 55 : x
  2. Step 2: Convert to fraction form
    42/55 = 55/x
  3. Step 3: Cross multiply
    42x = 55 × 55
  4. Step 4: Simplify right side
    42x = 3,025
  5. Step 5: Solve for x
    x = 3,025/42
  6. Step 6: Final answer
    x = 72.02

Related Problems

Find third proportional to 21 and 27.50
Half scale
Find third proportional to 84 and 110
Double scale
Find third proportional to 44 and 58
Similar ratio
Find third proportional to 63 and 82.50
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.31) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.