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Finding the Fourth Proportional to 189.57, 284.40 and 81.39

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Solution

The fourth proportional to 189.57, 284.40 and 81.39 is: 122.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.57 : 284.40 = 81.39 : x
  2. Step 2: Convert to fraction form
    189.57/284.40 = 81.39/x
  3. Step 3: Cross multiply
    189.57x = 284.40 × 81.39
  4. Step 4: Simplify right side
    189.57x = 23,147.32
  5. Step 5: Solve for x
    x = 23,147.32/189.57
  6. Step 6: Final answer
    x = 122.10

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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.