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Finding the Fourth Proportional to 62.89, 86.78 and 42.21

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Solution

The fourth proportional to 62.89, 86.78 and 42.21 is: 58.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    62.89 : 86.78 = 42.21 : x
  2. Step 2: Convert to fraction form
    62.89/86.78 = 42.21/x
  3. Step 3: Cross multiply
    62.89x = 86.78 × 42.21
  4. Step 4: Simplify right side
    62.89x = 3,663.09
  5. Step 5: Solve for x
    x = 3,663.09/62.89
  6. Step 6: Final answer
    x = 58.25

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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.