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Finding the Fourth Proportional to 431.34, 645.12 and 257.58

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Solution

The fourth proportional to 431.34, 645.12 and 257.58 is: 385.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.34 : 645.12 = 257.58 : x
  2. Step 2: Convert to fraction form
    431.34/645.12 = 257.58/x
  3. Step 3: Cross multiply
    431.34x = 645.12 × 257.58
  4. Step 4: Simplify right side
    431.34x = 166,170.01
  5. Step 5: Solve for x
    x = 166,170.01/431.34
  6. Step 6: Final answer
    x = 385.24

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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.