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Finding the Fourth Proportional to 805.47, 1,207.86 and 285.31

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Solution

The fourth proportional to 805.47, 1,207.86 and 285.31 is: 427.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.47 : 1,207.86 = 285.31 : x
  2. Step 2: Convert to fraction form
    805.47/1,207.86 = 285.31/x
  3. Step 3: Cross multiply
    805.47x = 1,207.86 × 285.31
  4. Step 4: Simplify right side
    805.47x = 344,614.54
  5. Step 5: Solve for x
    x = 344,614.54/805.47
  6. Step 6: Final answer
    x = 427.84

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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.