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Finding the Fourth Proportional to 814.78, 1,221.45 and 320.84

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Solution

The fourth proportional to 814.78, 1,221.45 and 320.84 is: 480.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    814.78 : 1,221.45 = 320.84 : x
  2. Step 2: Convert to fraction form
    814.78/1,221.45 = 320.84/x
  3. Step 3: Cross multiply
    814.78x = 1,221.45 × 320.84
  4. Step 4: Simplify right side
    814.78x = 391,886.56
  5. Step 5: Solve for x
    x = 391,886.56/814.78
  6. Step 6: Final answer
    x = 480.97

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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.