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Finding the Fourth Proportional to 821.11, 1,231.67 and 307.75

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Solution

The fourth proportional to 821.11, 1,231.67 and 307.75 is: 461.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.11 : 1,231.67 = 307.75 : x
  2. Step 2: Convert to fraction form
    821.11/1,231.67 = 307.75/x
  3. Step 3: Cross multiply
    821.11x = 1,231.67 × 307.75
  4. Step 4: Simplify right side
    821.11x = 379,046.44
  5. Step 5: Solve for x
    x = 379,046.44/821.11
  6. Step 6: Final answer
    x = 461.63

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Half scale
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Double scale
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Similar ratio
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1.5x scale

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.