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Finding the Fourth Proportional to 28.72, 42.75 and 28.64

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Solution

The fourth proportional to 28.72, 42.75 and 28.64 is: 42.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.72 : 42.75 = 28.64 : x
  2. Step 2: Convert to fraction form
    28.72/42.75 = 28.64/x
  3. Step 3: Cross multiply
    28.72x = 42.75 × 28.64
  4. Step 4: Simplify right side
    28.72x = 1,224.36
  5. Step 5: Solve for x
    x = 1,224.36/28.72
  6. Step 6: Final answer
    x = 42.63

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.