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Finding the Fourth Proportional to 291.90, 402.81 and 209.20

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Solution

The fourth proportional to 291.90, 402.81 and 209.20 is: 288.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.90 : 402.81 = 209.20 : x
  2. Step 2: Convert to fraction form
    291.90/402.81 = 209.20/x
  3. Step 3: Cross multiply
    291.90x = 402.81 × 209.20
  4. Step 4: Simplify right side
    291.90x = 84,267.85
  5. Step 5: Solve for x
    x = 84,267.85/291.90
  6. Step 6: Final answer
    x = 288.69

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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.