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Finding the Fourth Proportional to 28.82, 39.78 and 15.89

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Solution

The fourth proportional to 28.82, 39.78 and 15.89 is: 21.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.82 : 39.78 = 15.89 : x
  2. Step 2: Convert to fraction form
    28.82/39.78 = 15.89/x
  3. Step 3: Cross multiply
    28.82x = 39.78 × 15.89
  4. Step 4: Simplify right side
    28.82x = 631.83
  5. Step 5: Solve for x
    x = 631.83/28.82
  6. Step 6: Final answer
    x = 21.92

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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.