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Finding the Fourth Proportional to 189.71, 284.39 and 128.87

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Solution

The fourth proportional to 189.71, 284.39 and 128.87 is: 193.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    189.71 : 284.39 = 128.87 : x
  2. Step 2: Convert to fraction form
    189.71/284.39 = 128.87/x
  3. Step 3: Cross multiply
    189.71x = 284.39 × 128.87
  4. Step 4: Simplify right side
    189.71x = 36,647.27
  5. Step 5: Solve for x
    x = 36,647.27/189.71
  6. Step 6: Final answer
    x = 193.18

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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.