Home / 56-84-18

Finding the Fourth Proportional to 56, 84 and 18

Calculator

Solution

The fourth proportional to 56, 84 and 18 is: 27

Step by Step Solution

  1. Step 1: Write the proportion equation
    56 : 84 = 18 : x
  2. Step 2: Convert to fraction form
    56/84 = 18/x
  3. Step 3: Cross multiply
    56x = 84 × 18
  4. Step 4: Simplify right side
    56x = 1,512
  5. Step 5: Solve for x
    x = 1,512/56
  6. Step 6: Final answer
    x = 27

Related Problems

Find fourth proportional to 28, 42 and 9
Half scale
Find fourth proportional to 112, 168 and 36
Double scale
Find fourth proportional to 57, 85.50 and 19
Similar ratio
Find fourth proportional to 84, 126 and 27
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.