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Finding the Fourth Proportional to 6.40, 9.60 and 1.89

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Solution

The fourth proportional to 6.40, 9.60 and 1.89 is: 2.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.40 : 9.60 = 1.89 : x
  2. Step 2: Convert to fraction form
    6.40/9.60 = 1.89/x
  3. Step 3: Cross multiply
    6.40x = 9.60 × 1.89
  4. Step 4: Simplify right side
    6.40x = 18.18
  5. Step 5: Solve for x
    x = 18.18/6.40
  6. Step 6: Final answer
    x = 2.84

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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.