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Finding the Fourth Proportional to 420.24, 579.60 and 289.20

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Solution

The fourth proportional to 420.24, 579.60 and 289.20 is: 398.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.24 : 579.60 = 289.20 : x
  2. Step 2: Convert to fraction form
    420.24/579.60 = 289.20/x
  3. Step 3: Cross multiply
    420.24x = 579.60 × 289.20
  4. Step 4: Simplify right side
    420.24x = 167,620.32
  5. Step 5: Solve for x
    x = 167,620.32/420.24
  6. Step 6: Final answer
    x = 398.87

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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.