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Finding the Fourth Proportional to 384.20, 530.20 and 209.55

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Solution

The fourth proportional to 384.20, 530.20 and 209.55 is: 289.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    384.20 : 530.20 = 209.55 : x
  2. Step 2: Convert to fraction form
    384.20/530.20 = 209.55/x
  3. Step 3: Cross multiply
    384.20x = 530.20 × 209.55
  4. Step 4: Simplify right side
    384.20x = 111,103.41
  5. Step 5: Solve for x
    x = 111,103.41/384.20
  6. Step 6: Final answer
    x = 289.18

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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.