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Finding the Fourth Proportional to 28.72, 39.60 and 28.36

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Solution

The fourth proportional to 28.72, 39.60 and 28.36 is: 39.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.72 : 39.60 = 28.36 : x
  2. Step 2: Convert to fraction form
    28.72/39.60 = 28.36/x
  3. Step 3: Cross multiply
    28.72x = 39.60 × 28.36
  4. Step 4: Simplify right side
    28.72x = 1,123.06
  5. Step 5: Solve for x
    x = 1,123.06/28.72
  6. Step 6: Final answer
    x = 39.10

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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.