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Finding the Fourth Proportional to 420.35, 579.90 and 287.42

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Solution

The fourth proportional to 420.35, 579.90 and 287.42 is: 396.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.35 : 579.90 = 287.42 : x
  2. Step 2: Convert to fraction form
    420.35/579.90 = 287.42/x
  3. Step 3: Cross multiply
    420.35x = 579.90 × 287.42
  4. Step 4: Simplify right side
    420.35x = 166,674.86
  5. Step 5: Solve for x
    x = 166,674.86/420.35
  6. Step 6: Final answer
    x = 396.51

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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.