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Finding the Fourth Proportional to 813.87, 1,221 and 320.31

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Solution

The fourth proportional to 813.87, 1,221 and 320.31 is: 480.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.87 : 1,221 = 320.31 : x
  2. Step 2: Convert to fraction form
    813.87/1,221 = 320.31/x
  3. Step 3: Cross multiply
    813.87x = 1,221 × 320.31
  4. Step 4: Simplify right side
    813.87x = 391,098.51
  5. Step 5: Solve for x
    x = 391,098.51/813.87
  6. Step 6: Final answer
    x = 480.54

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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.