Home / 36-54-21.78

Finding the Fourth Proportional to 36, 54 and 21.78

Calculator

Solution

The fourth proportional to 36, 54 and 21.78 is: 32.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    36 : 54 = 21.78 : x
  2. Step 2: Convert to fraction form
    36/54 = 21.78/x
  3. Step 3: Cross multiply
    36x = 54 × 21.78
  4. Step 4: Simplify right side
    36x = 1,176.12
  5. Step 5: Solve for x
    x = 1,176.12/36
  6. Step 6: Final answer
    x = 32.67

Related Problems

Find fourth proportional to 18, 27 and 10.89
Half scale
Find fourth proportional to 72, 108 and 43.56
Double scale
Find fourth proportional to 37, 55.50 and 22.78
Similar ratio
Find fourth proportional to 54, 81 and 32.67
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.