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Finding the Fourth Proportional to 28.72, 39.81 and 28.29

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Solution

The fourth proportional to 28.72, 39.81 and 28.29 is: 39.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.72 : 39.81 = 28.29 : x
  2. Step 2: Convert to fraction form
    28.72/39.81 = 28.29/x
  3. Step 3: Cross multiply
    28.72x = 39.81 × 28.29
  4. Step 4: Simplify right side
    28.72x = 1,126.22
  5. Step 5: Solve for x
    x = 1,126.22/28.72
  6. Step 6: Final answer
    x = 39.22

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.