Home / 83.28-124.80-77.12

Finding the Fourth Proportional to 83.28, 124.80 and 77.12

Calculator

Solution

The fourth proportional to 83.28, 124.80 and 77.12 is: 115.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.28 : 124.80 = 77.12 : x
  2. Step 2: Convert to fraction form
    83.28/124.80 = 77.12/x
  3. Step 3: Cross multiply
    83.28x = 124.80 × 77.12
  4. Step 4: Simplify right side
    83.28x = 9,624.58
  5. Step 5: Solve for x
    x = 9,624.58/83.28
  6. Step 6: Final answer
    x = 115.57

Related Problems

Find fourth proportional to 41.64, 62.40 and 38.56
Half scale
Find fourth proportional to 166.56, 249.60 and 154.24
Double scale
Find fourth proportional to 84.28, 126.30 and 78.12
Similar ratio
Find fourth proportional to 124.92, 187.20 and 115.68
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.