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Finding the Fourth Proportional to 420.12, 579.52 and 289.12

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Solution

The fourth proportional to 420.12, 579.52 and 289.12 is: 398.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.12 : 579.52 = 289.12 : x
  2. Step 2: Convert to fraction form
    420.12/579.52 = 289.12/x
  3. Step 3: Cross multiply
    420.12x = 579.52 × 289.12
  4. Step 4: Simplify right side
    420.12x = 167,550.82
  5. Step 5: Solve for x
    x = 167,550.82/420.12
  6. Step 6: Final answer
    x = 398.82

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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.