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Finding the Fourth Proportional to 215.81, 297.85 and 128.48

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Solution

The fourth proportional to 215.81, 297.85 and 128.48 is: 177.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.81 : 297.85 = 128.48 : x
  2. Step 2: Convert to fraction form
    215.81/297.85 = 128.48/x
  3. Step 3: Cross multiply
    215.81x = 297.85 × 128.48
  4. Step 4: Simplify right side
    215.81x = 38,268.99
  5. Step 5: Solve for x
    x = 38,268.99/215.81
  6. Step 6: Final answer
    x = 177.33

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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.