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Finding the Fourth Proportional to 215.99, 298.14 and 128.66

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Solution

The fourth proportional to 215.99, 298.14 and 128.66 is: 177.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.99 : 298.14 = 128.66 : x
  2. Step 2: Convert to fraction form
    215.99/298.14 = 128.66/x
  3. Step 3: Cross multiply
    215.99x = 298.14 × 128.66
  4. Step 4: Simplify right side
    215.99x = 38,358.69
  5. Step 5: Solve for x
    x = 38,358.69/215.99
  6. Step 6: Final answer
    x = 177.59

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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.