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Finding the Fourth Proportional to 171.21, 256.66 and 79.86

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Solution

The fourth proportional to 171.21, 256.66 and 79.86 is: 119.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.21 : 256.66 = 79.86 : x
  2. Step 2: Convert to fraction form
    171.21/256.66 = 79.86/x
  3. Step 3: Cross multiply
    171.21x = 256.66 × 79.86
  4. Step 4: Simplify right side
    171.21x = 20,496.87
  5. Step 5: Solve for x
    x = 20,496.87/171.21
  6. Step 6: Final answer
    x = 119.72

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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.