Home / 82.15-123-70

Finding the Fourth Proportional to 82.15, 123 and 70

Calculator

Solution

The fourth proportional to 82.15, 123 and 70 is: 104.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.15 : 123 = 70 : x
  2. Step 2: Convert to fraction form
    82.15/123 = 70/x
  3. Step 3: Cross multiply
    82.15x = 123 × 70
  4. Step 4: Simplify right side
    82.15x = 8,610
  5. Step 5: Solve for x
    x = 8,610/82.15
  6. Step 6: Final answer
    x = 104.81

Related Problems

Find fourth proportional to 41.08, 61.50 and 35
Half scale
Find fourth proportional to 164.30, 246 and 140
Double scale
Find fourth proportional to 83.15, 124.50 and 71
Similar ratio
Find fourth proportional to 123.23, 184.50 and 105
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.