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Finding the Fourth Proportional to 643.47, 965.22 and 318.75

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Solution

The fourth proportional to 643.47, 965.22 and 318.75 is: 478.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.47 : 965.22 = 318.75 : x
  2. Step 2: Convert to fraction form
    643.47/965.22 = 318.75/x
  3. Step 3: Cross multiply
    643.47x = 965.22 × 318.75
  4. Step 4: Simplify right side
    643.47x = 307,663.88
  5. Step 5: Solve for x
    x = 307,663.88/643.47
  6. Step 6: Final answer
    x = 478.13

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Double scale
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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.