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Finding the Fourth Proportional to 430.91, 644.78 and 257.66

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Solution

The fourth proportional to 430.91, 644.78 and 257.66 is: 385.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    430.91 : 644.78 = 257.66 : x
  2. Step 2: Convert to fraction form
    430.91/644.78 = 257.66/x
  3. Step 3: Cross multiply
    430.91x = 644.78 × 257.66
  4. Step 4: Simplify right side
    430.91x = 166,129.50
  5. Step 5: Solve for x
    x = 166,129.50/430.91
  6. Step 6: Final answer
    x = 385.54

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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.