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Finding the Fourth Proportional to 420.62, 579.87 and 289.40

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Solution

The fourth proportional to 420.62, 579.87 and 289.40 is: 398.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.62 : 579.87 = 289.40 : x
  2. Step 2: Convert to fraction form
    420.62/579.87 = 289.40/x
  3. Step 3: Cross multiply
    420.62x = 579.87 × 289.40
  4. Step 4: Simplify right side
    420.62x = 167,811.48
  5. Step 5: Solve for x
    x = 167,811.48/420.62
  6. Step 6: Final answer
    x = 398.97

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.