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Finding the Fourth Proportional to 279.20, 385.08 and 209.28

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Solution

The fourth proportional to 279.20, 385.08 and 209.28 is: 288.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.20 : 385.08 = 209.28 : x
  2. Step 2: Convert to fraction form
    279.20/385.08 = 209.28/x
  3. Step 3: Cross multiply
    279.20x = 385.08 × 209.28
  4. Step 4: Simplify right side
    279.20x = 80,589.54
  5. Step 5: Solve for x
    x = 80,589.54/279.20
  6. Step 6: Final answer
    x = 288.64

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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.