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Finding the Fourth Proportional to 509.40, 764.10 and 387.90

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Solution

The fourth proportional to 509.40, 764.10 and 387.90 is: 581.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    509.40 : 764.10 = 387.90 : x
  2. Step 2: Convert to fraction form
    509.40/764.10 = 387.90/x
  3. Step 3: Cross multiply
    509.40x = 764.10 × 387.90
  4. Step 4: Simplify right side
    509.40x = 296,394.39
  5. Step 5: Solve for x
    x = 296,394.39/509.40
  6. Step 6: Final answer
    x = 581.85

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Double scale
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Similar ratio
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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.