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Finding the Fourth Proportional to 289.38, 399.61 and 211.15

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Solution

The fourth proportional to 289.38, 399.61 and 211.15 is: 291.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    289.38 : 399.61 = 211.15 : x
  2. Step 2: Convert to fraction form
    289.38/399.61 = 211.15/x
  3. Step 3: Cross multiply
    289.38x = 399.61 × 211.15
  4. Step 4: Simplify right side
    289.38x = 84,377.65
  5. Step 5: Solve for x
    x = 84,377.65/289.38
  6. Step 6: Final answer
    x = 291.58

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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.