Home / 14.28-19.71-7.81

Finding the Fourth Proportional to 14.28, 19.71 and 7.81

Calculator

Solution

The fourth proportional to 14.28, 19.71 and 7.81 is: 10.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    14.28 : 19.71 = 7.81 : x
  2. Step 2: Convert to fraction form
    14.28/19.71 = 7.81/x
  3. Step 3: Cross multiply
    14.28x = 19.71 × 7.81
  4. Step 4: Simplify right side
    14.28x = 153.97
  5. Step 5: Solve for x
    x = 153.97/14.28
  6. Step 6: Final answer
    x = 10.78

Related Problems

Find fourth proportional to 7.14, 9.85 and 3.91
Half scale
Find fourth proportional to 28.56, 39.42 and 15.63
Double scale
Find fourth proportional to 15.28, 21.09 and 8.81
Similar ratio
Find fourth proportional to 21.42, 29.56 and 11.72
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.