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Finding the Fourth Proportional to 431.37, 646.47 and 257.85

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Solution

The fourth proportional to 431.37, 646.47 and 257.85 is: 386.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.37 : 646.47 = 257.85 : x
  2. Step 2: Convert to fraction form
    431.37/646.47 = 257.85/x
  3. Step 3: Cross multiply
    431.37x = 646.47 × 257.85
  4. Step 4: Simplify right side
    431.37x = 166,692.29
  5. Step 5: Solve for x
    x = 166,692.29/431.37
  6. Step 6: Final answer
    x = 386.43

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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.