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Finding the Fourth Proportional to 311.90, 430.25 and 291.40

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Solution

The fourth proportional to 311.90, 430.25 and 291.40 is: 401.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.90 : 430.25 = 291.40 : x
  2. Step 2: Convert to fraction form
    311.90/430.25 = 291.40/x
  3. Step 3: Cross multiply
    311.90x = 430.25 × 291.40
  4. Step 4: Simplify right side
    311.90x = 125,372.32
  5. Step 5: Solve for x
    x = 125,372.32/311.90
  6. Step 6: Final answer
    x = 401.97

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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.