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Finding the Fourth Proportional to 805.49, 1,208.20 and 257.70

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Solution

The fourth proportional to 805.49, 1,208.20 and 257.70 is: 386.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.49 : 1,208.20 = 257.70 : x
  2. Step 2: Convert to fraction form
    805.49/1,208.20 = 257.70/x
  3. Step 3: Cross multiply
    805.49x = 1,208.20 × 257.70
  4. Step 4: Simplify right side
    805.49x = 311,353.14
  5. Step 5: Solve for x
    x = 311,353.14/805.49
  6. Step 6: Final answer
    x = 386.54

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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.