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Finding the Fourth Proportional to 512.40, 768.60 and 421.27

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Solution

The fourth proportional to 512.40, 768.60 and 421.27 is: 631.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    512.40 : 768.60 = 421.27 : x
  2. Step 2: Convert to fraction form
    512.40/768.60 = 421.27/x
  3. Step 3: Cross multiply
    512.40x = 768.60 × 421.27
  4. Step 4: Simplify right side
    512.40x = 323,788.12
  5. Step 5: Solve for x
    x = 323,788.12/512.40
  6. Step 6: Final answer
    x = 631.91

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Double scale
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Similar ratio
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1.5x scale

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.