Home / 123.15-169.87-81.76

Finding the Fourth Proportional to 123.15, 169.87 and 81.76

Calculator

Solution

The fourth proportional to 123.15, 169.87 and 81.76 is: 112.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    123.15 : 169.87 = 81.76 : x
  2. Step 2: Convert to fraction form
    123.15/169.87 = 81.76/x
  3. Step 3: Cross multiply
    123.15x = 169.87 × 81.76
  4. Step 4: Simplify right side
    123.15x = 13,888.57
  5. Step 5: Solve for x
    x = 13,888.57/123.15
  6. Step 6: Final answer
    x = 112.78

Related Problems

Find fourth proportional to 61.58, 84.94 and 40.88
Half scale
Find fourth proportional to 246.30, 339.74 and 163.52
Double scale
Find fourth proportional to 124.15, 171.25 and 82.76
Similar ratio
Find fourth proportional to 184.73, 254.81 and 122.64
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.