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Finding the Fourth Proportional to 442.21, 660.86 and 387.55

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Solution

The fourth proportional to 442.21, 660.86 and 387.55 is: 579.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    442.21 : 660.86 = 387.55 : x
  2. Step 2: Convert to fraction form
    442.21/660.86 = 387.55/x
  3. Step 3: Cross multiply
    442.21x = 660.86 × 387.55
  4. Step 4: Simplify right side
    442.21x = 256,116.29
  5. Step 5: Solve for x
    x = 256,116.29/442.21
  6. Step 6: Final answer
    x = 579.17

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.