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Finding the Fourth Proportional to 643.95, 966.74 and 428.49

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Solution

The fourth proportional to 643.95, 966.74 and 428.49 is: 643.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.95 : 966.74 = 428.49 : x
  2. Step 2: Convert to fraction form
    643.95/966.74 = 428.49/x
  3. Step 3: Cross multiply
    643.95x = 966.74 × 428.49
  4. Step 4: Simplify right side
    643.95x = 414,236.28
  5. Step 5: Solve for x
    x = 414,236.28/643.95
  6. Step 6: Final answer
    x = 643.27

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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.