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Finding the Fourth Proportional to 864.78, 1,297.20 and 215.52

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Solution

The fourth proportional to 864.78, 1,297.20 and 215.52 is: 323.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.78 : 1,297.20 = 215.52 : x
  2. Step 2: Convert to fraction form
    864.78/1,297.20 = 215.52/x
  3. Step 3: Cross multiply
    864.78x = 1,297.20 × 215.52
  4. Step 4: Simplify right side
    864.78x = 279,572.54
  5. Step 5: Solve for x
    x = 279,572.54/864.78
  6. Step 6: Final answer
    x = 323.29

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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.