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Finding the Fourth Proportional to 429.47, 643.78 and 169.28

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Solution

The fourth proportional to 429.47, 643.78 and 169.28 is: 253.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.47 : 643.78 = 169.28 : x
  2. Step 2: Convert to fraction form
    429.47/643.78 = 169.28/x
  3. Step 3: Cross multiply
    429.47x = 643.78 × 169.28
  4. Step 4: Simplify right side
    429.47x = 108,979.08
  5. Step 5: Solve for x
    x = 108,979.08/429.47
  6. Step 6: Final answer
    x = 253.75

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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.