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Finding the Fourth Proportional to 28.62, 39.45 and 21.69

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Solution

The fourth proportional to 28.62, 39.45 and 21.69 is: 29.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.62 : 39.45 = 21.69 : x
  2. Step 2: Convert to fraction form
    28.62/39.45 = 21.69/x
  3. Step 3: Cross multiply
    28.62x = 39.45 × 21.69
  4. Step 4: Simplify right side
    28.62x = 855.67
  5. Step 5: Solve for x
    x = 855.67/28.62
  6. Step 6: Final answer
    x = 29.90

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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.