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Finding the Fourth Proportional to 420.39, 579.75 and 280.44

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Solution

The fourth proportional to 420.39, 579.75 and 280.44 is: 386.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.39 : 579.75 = 280.44 : x
  2. Step 2: Convert to fraction form
    420.39/579.75 = 280.44/x
  3. Step 3: Cross multiply
    420.39x = 579.75 × 280.44
  4. Step 4: Simplify right side
    420.39x = 162,585.09
  5. Step 5: Solve for x
    x = 162,585.09/420.39
  6. Step 6: Final answer
    x = 386.75

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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.