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Finding the Fourth Proportional to 429.55, 643.65 and 320.20

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Solution

The fourth proportional to 429.55, 643.65 and 320.20 is: 479.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.55 : 643.65 = 320.20 : x
  2. Step 2: Convert to fraction form
    429.55/643.65 = 320.20/x
  3. Step 3: Cross multiply
    429.55x = 643.65 × 320.20
  4. Step 4: Simplify right side
    429.55x = 206,096.73
  5. Step 5: Solve for x
    x = 206,096.73/429.55
  6. Step 6: Final answer
    x = 479.80

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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.