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Finding the Fourth Proportional to 215.81, 297.72 and 128.46

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Solution

The fourth proportional to 215.81, 297.72 and 128.46 is: 177.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.81 : 297.72 = 128.46 : x
  2. Step 2: Convert to fraction form
    215.81/297.72 = 128.46/x
  3. Step 3: Cross multiply
    215.81x = 297.72 × 128.46
  4. Step 4: Simplify right side
    215.81x = 38,245.11
  5. Step 5: Solve for x
    x = 38,245.11/215.81
  6. Step 6: Final answer
    x = 177.22

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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.