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Finding the Fourth Proportional to 643.85, 965.81 and 319.13

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Solution

The fourth proportional to 643.85, 965.81 and 319.13 is: 478.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.85 : 965.81 = 319.13 : x
  2. Step 2: Convert to fraction form
    643.85/965.81 = 319.13/x
  3. Step 3: Cross multiply
    643.85x = 965.81 × 319.13
  4. Step 4: Simplify right side
    643.85x = 308,214.91
  5. Step 5: Solve for x
    x = 308,214.91/643.85
  6. Step 6: Final answer
    x = 478.71

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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.