Home / 84-126-68

Finding the Fourth Proportional to 84, 126 and 68

Calculator

Solution

The fourth proportional to 84, 126 and 68 is: 102

Step by Step Solution

  1. Step 1: Write the proportion equation
    84 : 126 = 68 : x
  2. Step 2: Convert to fraction form
    84/126 = 68/x
  3. Step 3: Cross multiply
    84x = 126 × 68
  4. Step 4: Simplify right side
    84x = 8,568
  5. Step 5: Solve for x
    x = 8,568/84
  6. Step 6: Final answer
    x = 102

Related Problems

Find fourth proportional to 42, 63 and 34
Half scale
Find fourth proportional to 168, 252 and 136
Double scale
Find fourth proportional to 85, 127.50 and 69
Similar ratio
Find fourth proportional to 126, 189 and 102
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.