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Finding the Fourth Proportional to 431.32, 645.83 and 257.56

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Solution

The fourth proportional to 431.32, 645.83 and 257.56 is: 385.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.32 : 645.83 = 257.56 : x
  2. Step 2: Convert to fraction form
    431.32/645.83 = 257.56/x
  3. Step 3: Cross multiply
    431.32x = 645.83 × 257.56
  4. Step 4: Simplify right side
    431.32x = 166,337.07
  5. Step 5: Solve for x
    x = 166,337.07/431.32
  6. Step 6: Final answer
    x = 385.65

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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.