Home / 88.38-121.86-81.90

Finding the Fourth Proportional to 88.38, 121.86 and 81.90

Calculator

Solution

The fourth proportional to 88.38, 121.86 and 81.90 is: 112.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.38 : 121.86 = 81.90 : x
  2. Step 2: Convert to fraction form
    88.38/121.86 = 81.90/x
  3. Step 3: Cross multiply
    88.38x = 121.86 × 81.90
  4. Step 4: Simplify right side
    88.38x = 9,980.33
  5. Step 5: Solve for x
    x = 9,980.33/88.38
  6. Step 6: Final answer
    x = 112.93

Related Problems

Find fourth proportional to 44.19, 60.93 and 40.95
Half scale
Find fourth proportional to 176.76, 243.72 and 163.80
Double scale
Find fourth proportional to 89.38, 123.24 and 82.90
Similar ratio
Find fourth proportional to 132.57, 182.79 and 122.85
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.