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Finding the Fourth Proportional to 429.55, 643.79 and 213.07

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Solution

The fourth proportional to 429.55, 643.79 and 213.07 is: 319.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.55 : 643.79 = 213.07 : x
  2. Step 2: Convert to fraction form
    429.55/643.79 = 213.07/x
  3. Step 3: Cross multiply
    429.55x = 643.79 × 213.07
  4. Step 4: Simplify right side
    429.55x = 137,171.27
  5. Step 5: Solve for x
    x = 137,171.27/429.55
  6. Step 6: Final answer
    x = 319.34

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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.