Home / 70-100

Finding the Third Proportional to 70 and 100

Calculator

Solution

The third proportional to 70 and 100 is: 142.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    70 : 100 = 100 : x
  2. Step 2: Convert to fraction form
    70/100 = 100/x
  3. Step 3: Cross multiply
    70x = 100 × 100
  4. Step 4: Simplify right side
    70x = 10,000
  5. Step 5: Solve for x
    x = 10,000/70
  6. Step 6: Final answer
    x = 142.86

Related Problems

Find third proportional to 35 and 50
Half scale
Find third proportional to 140 and 200
Double scale
Find third proportional to 72 and 103
Similar ratio
Find third proportional to 105 and 150
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.43) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.