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Finding the Fourth Proportional to 644.48, 965.28 and 427.76

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Solution

The fourth proportional to 644.48, 965.28 and 427.76 is: 640.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.48 : 965.28 = 427.76 : x
  2. Step 2: Convert to fraction form
    644.48/965.28 = 427.76/x
  3. Step 3: Cross multiply
    644.48x = 965.28 × 427.76
  4. Step 4: Simplify right side
    644.48x = 412,908.17
  5. Step 5: Solve for x
    x = 412,908.17/644.48
  6. Step 6: Final answer
    x = 640.68

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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.