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Finding the Fourth Proportional to 659.27, 989.96 and 428.72

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Solution

The fourth proportional to 659.27, 989.96 and 428.72 is: 643.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.27 : 989.96 = 428.72 : x
  2. Step 2: Convert to fraction form
    659.27/989.96 = 428.72/x
  3. Step 3: Cross multiply
    659.27x = 989.96 × 428.72
  4. Step 4: Simplify right side
    659.27x = 424,408.56
  5. Step 5: Solve for x
    x = 424,408.56/659.27
  6. Step 6: Final answer
    x = 643.76

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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.