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Finding the Fourth Proportional to 642.67, 965.09 and 420.68

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Solution

The fourth proportional to 642.67, 965.09 and 420.68 is: 631.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.67 : 965.09 = 420.68 : x
  2. Step 2: Convert to fraction form
    642.67/965.09 = 420.68/x
  3. Step 3: Cross multiply
    642.67x = 965.09 × 420.68
  4. Step 4: Simplify right side
    642.67x = 405,994.06
  5. Step 5: Solve for x
    x = 405,994.06/642.67
  6. Step 6: Final answer
    x = 631.73

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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.