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Finding the Fourth Proportional to 281.69, 420.90 and 215.44

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Solution

The fourth proportional to 281.69, 420.90 and 215.44 is: 321.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.69 : 420.90 = 215.44 : x
  2. Step 2: Convert to fraction form
    281.69/420.90 = 215.44/x
  3. Step 3: Cross multiply
    281.69x = 420.90 × 215.44
  4. Step 4: Simplify right side
    281.69x = 90,676.59
  5. Step 5: Solve for x
    x = 90,676.59/281.69
  6. Step 6: Final answer
    x = 321.90

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.