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Finding the Fourth Proportional to 171.85, 257.86 and 69.21

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Solution

The fourth proportional to 171.85, 257.86 and 69.21 is: 103.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    171.85 : 257.86 = 69.21 : x
  2. Step 2: Convert to fraction form
    171.85/257.86 = 69.21/x
  3. Step 3: Cross multiply
    171.85x = 257.86 × 69.21
  4. Step 4: Simplify right side
    171.85x = 17,846.19
  5. Step 5: Solve for x
    x = 17,846.19/171.85
  6. Step 6: Final answer
    x = 103.85

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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.