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Finding the Fourth Proportional to 429.20, 643.20 and 318.65

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Solution

The fourth proportional to 429.20, 643.20 and 318.65 is: 477.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.20 : 643.20 = 318.65 : x
  2. Step 2: Convert to fraction form
    429.20/643.20 = 318.65/x
  3. Step 3: Cross multiply
    429.20x = 643.20 × 318.65
  4. Step 4: Simplify right side
    429.20x = 204,955.68
  5. Step 5: Solve for x
    x = 204,955.68/429.20
  6. Step 6: Final answer
    x = 477.53

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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.