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Finding the Fourth Proportional to 5.28, 7.91 and 5.21

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Solution

The fourth proportional to 5.28, 7.91 and 5.21 is: 7.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.28 : 7.91 = 5.21 : x
  2. Step 2: Convert to fraction form
    5.28/7.91 = 5.21/x
  3. Step 3: Cross multiply
    5.28x = 7.91 × 5.21
  4. Step 4: Simplify right side
    5.28x = 41.15
  5. Step 5: Solve for x
    x = 41.15/5.28
  6. Step 6: Final answer
    x = 7.79

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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.