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Finding the Fourth Proportional to 215.35, 322.91 and 128.69

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Solution

The fourth proportional to 215.35, 322.91 and 128.69 is: 192.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.35 : 322.91 = 128.69 : x
  2. Step 2: Convert to fraction form
    215.35/322.91 = 128.69/x
  3. Step 3: Cross multiply
    215.35x = 322.91 × 128.69
  4. Step 4: Simplify right side
    215.35x = 41,555.29
  5. Step 5: Solve for x
    x = 41,555.29/215.35
  6. Step 6: Final answer
    x = 192.97

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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.