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Finding the Fourth Proportional to 257.65, 387.28 and 212.96

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Solution

The fourth proportional to 257.65, 387.28 and 212.96 is: 320.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.65 : 387.28 = 212.96 : x
  2. Step 2: Convert to fraction form
    257.65/387.28 = 212.96/x
  3. Step 3: Cross multiply
    257.65x = 387.28 × 212.96
  4. Step 4: Simplify right side
    257.65x = 82,476.38
  5. Step 5: Solve for x
    x = 82,476.38/257.65
  6. Step 6: Final answer
    x = 320.11

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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.