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Finding the Fourth Proportional to 281.76, 390.92 and 279.28

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Solution

The fourth proportional to 281.76, 390.92 and 279.28 is: 387.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    281.76 : 390.92 = 279.28 : x
  2. Step 2: Convert to fraction form
    281.76/390.92 = 279.28/x
  3. Step 3: Cross multiply
    281.76x = 390.92 × 279.28
  4. Step 4: Simplify right side
    281.76x = 109,176.14
  5. Step 5: Solve for x
    x = 109,176.14/281.76
  6. Step 6: Final answer
    x = 387.48

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.