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Finding the Fourth Proportional to 643.69, 965.64 and 319.06

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Solution

The fourth proportional to 643.69, 965.64 and 319.06 is: 478.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.69 : 965.64 = 319.06 : x
  2. Step 2: Convert to fraction form
    643.69/965.64 = 319.06/x
  3. Step 3: Cross multiply
    643.69x = 965.64 × 319.06
  4. Step 4: Simplify right side
    643.69x = 308,097.10
  5. Step 5: Solve for x
    x = 308,097.10/643.69
  6. Step 6: Final answer
    x = 478.64

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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.