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Finding the Fourth Proportional to 28.49, 42.75 and 8.21

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Solution

The fourth proportional to 28.49, 42.75 and 8.21 is: 12.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.49 : 42.75 = 8.21 : x
  2. Step 2: Convert to fraction form
    28.49/42.75 = 8.21/x
  3. Step 3: Cross multiply
    28.49x = 42.75 × 8.21
  4. Step 4: Simplify right side
    28.49x = 350.76
  5. Step 5: Solve for x
    x = 350.76/28.49
  6. Step 6: Final answer
    x = 12.31

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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.