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Finding the Fourth Proportional to 420.28, 579.57 and 387.17

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Solution

The fourth proportional to 420.28, 579.57 and 387.17 is: 533.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.28 : 579.57 = 387.17 : x
  2. Step 2: Convert to fraction form
    420.28/579.57 = 387.17/x
  3. Step 3: Cross multiply
    420.28x = 579.57 × 387.17
  4. Step 4: Simplify right side
    420.28x = 224,392.12
  5. Step 5: Solve for x
    x = 224,392.12/420.28
  6. Step 6: Final answer
    x = 533.91

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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.