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Finding the Fourth Proportional to 28.47, 42.72 and 12.45

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Solution

The fourth proportional to 28.47, 42.72 and 12.45 is: 18.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.47 : 42.72 = 12.45 : x
  2. Step 2: Convert to fraction form
    28.47/42.72 = 12.45/x
  3. Step 3: Cross multiply
    28.47x = 42.72 × 12.45
  4. Step 4: Simplify right side
    28.47x = 531.86
  5. Step 5: Solve for x
    x = 531.86/28.47
  6. Step 6: Final answer
    x = 18.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.