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Finding the Fourth Proportional to 215.66, 297.68 and 128.39

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Solution

The fourth proportional to 215.66, 297.68 and 128.39 is: 177.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.66 : 297.68 = 128.39 : x
  2. Step 2: Convert to fraction form
    215.66/297.68 = 128.39/x
  3. Step 3: Cross multiply
    215.66x = 297.68 × 128.39
  4. Step 4: Simplify right side
    215.66x = 38,217.00
  5. Step 5: Solve for x
    x = 38,217.00/215.66
  6. Step 6: Final answer
    x = 177.21

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.