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Finding the Fourth Proportional to 643.39, 965.20 and 278.19

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Solution

The fourth proportional to 643.39, 965.20 and 278.19 is: 417.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.39 : 965.20 = 278.19 : x
  2. Step 2: Convert to fraction form
    643.39/965.20 = 278.19/x
  3. Step 3: Cross multiply
    643.39x = 965.20 × 278.19
  4. Step 4: Simplify right side
    643.39x = 268,508.99
  5. Step 5: Solve for x
    x = 268,508.99/643.39
  6. Step 6: Final answer
    x = 417.33

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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.