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Finding the Fourth Proportional to 76.21, 105.19 and 63.91

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Solution

The fourth proportional to 76.21, 105.19 and 63.91 is: 88.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.21 : 105.19 = 63.91 : x
  2. Step 2: Convert to fraction form
    76.21/105.19 = 63.91/x
  3. Step 3: Cross multiply
    76.21x = 105.19 × 63.91
  4. Step 4: Simplify right side
    76.21x = 6,722.69
  5. Step 5: Solve for x
    x = 6,722.69/76.21
  6. Step 6: Final answer
    x = 88.21

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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.