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Finding the Fourth Proportional to 429.57, 643.95 and 285.39

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Solution

The fourth proportional to 429.57, 643.95 and 285.39 is: 427.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.57 : 643.95 = 285.39 : x
  2. Step 2: Convert to fraction form
    429.57/643.95 = 285.39/x
  3. Step 3: Cross multiply
    429.57x = 643.95 × 285.39
  4. Step 4: Simplify right side
    429.57x = 183,776.89
  5. Step 5: Solve for x
    x = 183,776.89/429.57
  6. Step 6: Final answer
    x = 427.82

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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.