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Finding the Fourth Proportional to 420.40, 631.14 and 396.64

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Solution

The fourth proportional to 420.40, 631.14 and 396.64 is: 595.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.40 : 631.14 = 396.64 : x
  2. Step 2: Convert to fraction form
    420.40/631.14 = 396.64/x
  3. Step 3: Cross multiply
    420.40x = 631.14 × 396.64
  4. Step 4: Simplify right side
    420.40x = 250,335.37
  5. Step 5: Solve for x
    x = 250,335.37/420.40
  6. Step 6: Final answer
    x = 595.47

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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.