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Finding the Fourth Proportional to 865.47, 1,298.81 and 378.66

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Solution

The fourth proportional to 865.47, 1,298.81 and 378.66 is: 568.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.47 : 1,298.81 = 378.66 : x
  2. Step 2: Convert to fraction form
    865.47/1,298.81 = 378.66/x
  3. Step 3: Cross multiply
    865.47x = 1,298.81 × 378.66
  4. Step 4: Simplify right side
    865.47x = 491,808.34
  5. Step 5: Solve for x
    x = 491,808.34/865.47
  6. Step 6: Final answer
    x = 568.26

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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.