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Finding the Fourth Proportional to 257.72, 385.74 and 212.76

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Solution

The fourth proportional to 257.72, 385.74 and 212.76 is: 318.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    257.72 : 385.74 = 212.76 : x
  2. Step 2: Convert to fraction form
    257.72/385.74 = 212.76/x
  3. Step 3: Cross multiply
    257.72x = 385.74 × 212.76
  4. Step 4: Simplify right side
    257.72x = 82,070.04
  5. Step 5: Solve for x
    x = 82,070.04/257.72
  6. Step 6: Final answer
    x = 318.45

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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.