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Finding the Fourth Proportional to 61.21, 84.46 and 42.85

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Solution

The fourth proportional to 61.21, 84.46 and 42.85 is: 59.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.21 : 84.46 = 42.85 : x
  2. Step 2: Convert to fraction form
    61.21/84.46 = 42.85/x
  3. Step 3: Cross multiply
    61.21x = 84.46 × 42.85
  4. Step 4: Simplify right side
    61.21x = 3,618.47
  5. Step 5: Solve for x
    x = 3,618.47/61.21
  6. Step 6: Final answer
    x = 59.12

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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.