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Finding the Fourth Proportional to 865.19, 1,297.80 and 215.91

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Solution

The fourth proportional to 865.19, 1,297.80 and 215.91 is: 323.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.19 : 1,297.80 = 215.91 : x
  2. Step 2: Convert to fraction form
    865.19/1,297.80 = 215.91/x
  3. Step 3: Cross multiply
    865.19x = 1,297.80 × 215.91
  4. Step 4: Simplify right side
    865.19x = 280,208.00
  5. Step 5: Solve for x
    x = 280,208.00/865.19
  6. Step 6: Final answer
    x = 323.87

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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.