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Finding the Fourth Proportional to 429.46, 643.56 and 212.61

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Solution

The fourth proportional to 429.46, 643.56 and 212.61 is: 318.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.46 : 643.56 = 212.61 : x
  2. Step 2: Convert to fraction form
    429.46/643.56 = 212.61/x
  3. Step 3: Cross multiply
    429.46x = 643.56 × 212.61
  4. Step 4: Simplify right side
    429.46x = 136,827.29
  5. Step 5: Solve for x
    x = 136,827.29/429.46
  6. Step 6: Final answer
    x = 318.60

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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.