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Finding the Fourth Proportional to 865.78, 1,297.74 and 427.34

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Solution

The fourth proportional to 865.78, 1,297.74 and 427.34 is: 640.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.78 : 1,297.74 = 427.34 : x
  2. Step 2: Convert to fraction form
    865.78/1,297.74 = 427.34/x
  3. Step 3: Cross multiply
    865.78x = 1,297.74 × 427.34
  4. Step 4: Simplify right side
    865.78x = 554,576.21
  5. Step 5: Solve for x
    x = 554,576.21/865.78
  6. Step 6: Final answer
    x = 640.55

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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.