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Finding the Fourth Proportional to 387.71, 581.76 and 257.80

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Solution

The fourth proportional to 387.71, 581.76 and 257.80 is: 386.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.71 : 581.76 = 257.80 : x
  2. Step 2: Convert to fraction form
    387.71/581.76 = 257.80/x
  3. Step 3: Cross multiply
    387.71x = 581.76 × 257.80
  4. Step 4: Simplify right side
    387.71x = 149,976.92
  5. Step 5: Solve for x
    x = 149,976.92/387.71
  6. Step 6: Final answer
    x = 386.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.