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Finding the Fourth Proportional to 215.90, 297.83 and 128.56

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Solution

The fourth proportional to 215.90, 297.83 and 128.56 is: 177.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.90 : 297.83 = 128.56 : x
  2. Step 2: Convert to fraction form
    215.90/297.83 = 128.56/x
  3. Step 3: Cross multiply
    215.90x = 297.83 × 128.56
  4. Step 4: Simplify right side
    215.90x = 38,286.89
  5. Step 5: Solve for x
    x = 38,286.89/215.90
  6. Step 6: Final answer
    x = 177.34

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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.