Home / 23.09-31.85-20.78

Finding the Fourth Proportional to 23.09, 31.85 and 20.78

Calculator

Solution

The fourth proportional to 23.09, 31.85 and 20.78 is: 28.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    23.09 : 31.85 = 20.78 : x
  2. Step 2: Convert to fraction form
    23.09/31.85 = 20.78/x
  3. Step 3: Cross multiply
    23.09x = 31.85 × 20.78
  4. Step 4: Simplify right side
    23.09x = 661.74
  5. Step 5: Solve for x
    x = 661.74/23.09
  6. Step 6: Final answer
    x = 28.66

Related Problems

Find fourth proportional to 11.55, 15.92 and 10.39
Half scale
Find fourth proportional to 46.18, 63.69 and 41.56
Double scale
Find fourth proportional to 24.09, 33.22 and 21.78
Similar ratio
Find fourth proportional to 34.64, 47.77 and 31.17
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.