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Finding the Fourth Proportional to 429.11, 643.26 and 212.57

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Solution

The fourth proportional to 429.11, 643.26 and 212.57 is: 318.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.11 : 643.26 = 212.57 : x
  2. Step 2: Convert to fraction form
    429.11/643.26 = 212.57/x
  3. Step 3: Cross multiply
    429.11x = 643.26 × 212.57
  4. Step 4: Simplify right side
    429.11x = 136,737.78
  5. Step 5: Solve for x
    x = 136,737.78/429.11
  6. Step 6: Final answer
    x = 318.65

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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.