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Finding the Fourth Proportional to 281.38, 421.18 and 208.21

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Solution

The fourth proportional to 281.38, 421.18 and 208.21 is: 311.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.38 : 421.18 = 208.21 : x
  2. Step 2: Convert to fraction form
    281.38/421.18 = 208.21/x
  3. Step 3: Cross multiply
    281.38x = 421.18 × 208.21
  4. Step 4: Simplify right side
    281.38x = 87,693.89
  5. Step 5: Solve for x
    x = 87,693.89/281.38
  6. Step 6: Final answer
    x = 311.66

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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.