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Finding the Fourth Proportional to 420.17, 579.85 and 280.20

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Solution

The fourth proportional to 420.17, 579.85 and 280.20 is: 386.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.17 : 579.85 = 280.20 : x
  2. Step 2: Convert to fraction form
    420.17/579.85 = 280.20/x
  3. Step 3: Cross multiply
    420.17x = 579.85 × 280.20
  4. Step 4: Simplify right side
    420.17x = 162,471.07
  5. Step 5: Solve for x
    x = 162,471.07/420.17
  6. Step 6: Final answer
    x = 386.68

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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.