Home / 42-81.50

Finding the Third Proportional to 42 and 81.50

Calculator

Solution

The third proportional to 42 and 81.50 is: 158.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    42 : 81.50 = 81.50 : x
  2. Step 2: Convert to fraction form
    42/81.50 = 81.50/x
  3. Step 3: Cross multiply
    42x = 81.50 × 81.50
  4. Step 4: Simplify right side
    42x = 6,642.25
  5. Step 5: Solve for x
    x = 6,642.25/42
  6. Step 6: Final answer
    x = 158.15

Related Problems

Find third proportional to 21 and 40.75
Half scale
Find third proportional to 84 and 163
Double scale
Find third proportional to 44 and 85
Similar ratio
Find third proportional to 63 and 122.25
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.94) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.