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Finding the Fourth Proportional to 640.99, 961.76 and 381.49

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Solution

The fourth proportional to 640.99, 961.76 and 381.49 is: 572.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.99 : 961.76 = 381.49 : x
  2. Step 2: Convert to fraction form
    640.99/961.76 = 381.49/x
  3. Step 3: Cross multiply
    640.99x = 961.76 × 381.49
  4. Step 4: Simplify right side
    640.99x = 366,895.11
  5. Step 5: Solve for x
    x = 366,895.11/640.99
  6. Step 6: Final answer
    x = 572.39

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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.