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Finding the Fourth Proportional to 5.45, 8.15 and 5.20

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Solution

The fourth proportional to 5.45, 8.15 and 5.20 is: 7.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.45 : 8.15 = 5.20 : x
  2. Step 2: Convert to fraction form
    5.45/8.15 = 5.20/x
  3. Step 3: Cross multiply
    5.45x = 8.15 × 5.20
  4. Step 4: Simplify right side
    5.45x = 42.38
  5. Step 5: Solve for x
    x = 42.38/5.45
  6. Step 6: Final answer
    x = 7.78

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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.