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Finding the Fourth Proportional to 126.13, 189.16 and 85.81

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Solution

The fourth proportional to 126.13, 189.16 and 85.81 is: 128.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    126.13 : 189.16 = 85.81 : x
  2. Step 2: Convert to fraction form
    126.13/189.16 = 85.81/x
  3. Step 3: Cross multiply
    126.13x = 189.16 × 85.81
  4. Step 4: Simplify right side
    126.13x = 16,231.39
  5. Step 5: Solve for x
    x = 16,231.39/126.13
  6. Step 6: Final answer
    x = 128.69

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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.