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Finding the Fourth Proportional to 171.32, 256.96 and 85.76

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Solution

The fourth proportional to 171.32, 256.96 and 85.76 is: 128.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.32 : 256.96 = 85.76 : x
  2. Step 2: Convert to fraction form
    171.32/256.96 = 85.76/x
  3. Step 3: Cross multiply
    171.32x = 256.96 × 85.76
  4. Step 4: Simplify right side
    171.32x = 22,036.89
  5. Step 5: Solve for x
    x = 22,036.89/171.32
  6. Step 6: Final answer
    x = 128.63

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.