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Finding the Fourth Proportional to 805.70, 1,208.73 and 257.91

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Solution

The fourth proportional to 805.70, 1,208.73 and 257.91 is: 386.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.70 : 1,208.73 = 257.91 : x
  2. Step 2: Convert to fraction form
    805.70/1,208.73 = 257.91/x
  3. Step 3: Cross multiply
    805.70x = 1,208.73 × 257.91
  4. Step 4: Simplify right side
    805.70x = 311,743.55
  5. Step 5: Solve for x
    x = 311,743.55/805.70
  6. Step 6: Final answer
    x = 386.92

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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.