Home / 189.98-285.08-81.78

Finding the Fourth Proportional to 189.98, 285.08 and 81.78

Calculator

Solution

The fourth proportional to 189.98, 285.08 and 81.78 is: 122.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.98 : 285.08 = 81.78 : x
  2. Step 2: Convert to fraction form
    189.98/285.08 = 81.78/x
  3. Step 3: Cross multiply
    189.98x = 285.08 × 81.78
  4. Step 4: Simplify right side
    189.98x = 23,313.84
  5. Step 5: Solve for x
    x = 23,313.84/189.98
  6. Step 6: Final answer
    x = 122.72

Related Problems

Find fourth proportional to 94.99, 142.54 and 40.89
Half scale
Find fourth proportional to 379.96, 570.16 and 163.56
Double scale
Find fourth proportional to 190.98, 286.58 and 82.78
Similar ratio
Find fourth proportional to 284.97, 427.62 and 122.67
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.