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Finding the Fourth Proportional to 2.09, 2.88 and 1.28

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Solution

The fourth proportional to 2.09, 2.88 and 1.28 is: 1.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    2.09 : 2.88 = 1.28 : x
  2. Step 2: Convert to fraction form
    2.09/2.88 = 1.28/x
  3. Step 3: Cross multiply
    2.09x = 2.88 × 1.28
  4. Step 4: Simplify right side
    2.09x = 3.68
  5. Step 5: Solve for x
    x = 3.68/2.09
  6. Step 6: Final answer
    x = 1.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.