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Finding the Fourth Proportional to 643.68, 965.12 and 319.28

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Solution

The fourth proportional to 643.68, 965.12 and 319.28 is: 478.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.68 : 965.12 = 319.28 : x
  2. Step 2: Convert to fraction form
    643.68/965.12 = 319.28/x
  3. Step 3: Cross multiply
    643.68x = 965.12 × 319.28
  4. Step 4: Simplify right side
    643.68x = 308,137.09
  5. Step 5: Solve for x
    x = 308,137.09/643.68
  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.