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Finding the Fourth Proportional to 421.72, 631.13 and 257.11

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Solution

The fourth proportional to 421.72, 631.13 and 257.11 is: 384.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.72 : 631.13 = 257.11 : x
  2. Step 2: Convert to fraction form
    421.72/631.13 = 257.11/x
  3. Step 3: Cross multiply
    421.72x = 631.13 × 257.11
  4. Step 4: Simplify right side
    421.72x = 162,266.97
  5. Step 5: Solve for x
    x = 162,266.97/421.72
  6. Step 6: Final answer
    x = 384.77

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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.