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Finding the Fourth Proportional to 420.39, 580.33 and 278.69

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Solution

The fourth proportional to 420.39, 580.33 and 278.69 is: 384.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.39 : 580.33 = 278.69 : x
  2. Step 2: Convert to fraction form
    420.39/580.33 = 278.69/x
  3. Step 3: Cross multiply
    420.39x = 580.33 × 278.69
  4. Step 4: Simplify right side
    420.39x = 161,732.17
  5. Step 5: Solve for x
    x = 161,732.17/420.39
  6. Step 6: Final answer
    x = 384.72

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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.