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Finding the Fourth Proportional to 432.20, 645.28 and 427.64

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Solution

The fourth proportional to 432.20, 645.28 and 427.64 is: 638.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    432.20 : 645.28 = 427.64 : x
  2. Step 2: Convert to fraction form
    432.20/645.28 = 427.64/x
  3. Step 3: Cross multiply
    432.20x = 645.28 × 427.64
  4. Step 4: Simplify right side
    432.20x = 275,947.54
  5. Step 5: Solve for x
    x = 275,947.54/432.20
  6. Step 6: Final answer
    x = 638.47

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.