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Finding the Fourth Proportional to 41.21, 61.78 and 20.91

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Solution

The fourth proportional to 41.21, 61.78 and 20.91 is: 31.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    41.21 : 61.78 = 20.91 : x
  2. Step 2: Convert to fraction form
    41.21/61.78 = 20.91/x
  3. Step 3: Cross multiply
    41.21x = 61.78 × 20.91
  4. Step 4: Simplify right side
    41.21x = 1,291.77
  5. Step 5: Solve for x
    x = 1,291.77/41.21
  6. Step 6: Final answer
    x = 31.35

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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.