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Finding the Fourth Proportional to 486.40, 671.36 and 320.80

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Solution

The fourth proportional to 486.40, 671.36 and 320.80 is: 442.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.40 : 671.36 = 320.80 : x
  2. Step 2: Convert to fraction form
    486.40/671.36 = 320.80/x
  3. Step 3: Cross multiply
    486.40x = 671.36 × 320.80
  4. Step 4: Simplify right side
    486.40x = 215,372.29
  5. Step 5: Solve for x
    x = 215,372.29/486.40
  6. Step 6: Final answer
    x = 442.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.