Home / 54.20-81.31-31.39

Finding the Fourth Proportional to 54.20, 81.31 and 31.39

Calculator

Solution

The fourth proportional to 54.20, 81.31 and 31.39 is: 47.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    54.20 : 81.31 = 31.39 : x
  2. Step 2: Convert to fraction form
    54.20/81.31 = 31.39/x
  3. Step 3: Cross multiply
    54.20x = 81.31 × 31.39
  4. Step 4: Simplify right side
    54.20x = 2,552.32
  5. Step 5: Solve for x
    x = 2,552.32/54.20
  6. Step 6: Final answer
    x = 47.09

Related Problems

Find fourth proportional to 27.10, 40.66 and 15.70
Half scale
Find fourth proportional to 108.40, 162.62 and 62.78
Double scale
Find fourth proportional to 55.20, 82.81 and 32.39
Similar ratio
Find fourth proportional to 81.30, 121.97 and 47.09
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.