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Finding the Fourth Proportional to 778.67, 1,076.11 and 638.57

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Solution

The fourth proportional to 778.67, 1,076.11 and 638.57 is: 882.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    778.67 : 1,076.11 = 638.57 : x
  2. Step 2: Convert to fraction form
    778.67/1,076.11 = 638.57/x
  3. Step 3: Cross multiply
    778.67x = 1,076.11 × 638.57
  4. Step 4: Simplify right side
    778.67x = 687,171.56
  5. Step 5: Solve for x
    x = 687,171.56/778.67
  6. Step 6: Final answer
    x = 882.49

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.