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Finding the Fourth Proportional to 5.21, 7.82 and 4.78

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Solution

The fourth proportional to 5.21, 7.82 and 4.78 is: 7.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.21 : 7.82 = 4.78 : x
  2. Step 2: Convert to fraction form
    5.21/7.82 = 4.78/x
  3. Step 3: Cross multiply
    5.21x = 7.82 × 4.78
  4. Step 4: Simplify right side
    5.21x = 37.38
  5. Step 5: Solve for x
    x = 37.38/5.21
  6. Step 6: Final answer
    x = 7.17

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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.