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Finding the Fourth Proportional to 4.20, 5.81 and 2.91

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Solution

The fourth proportional to 4.20, 5.81 and 2.91 is: 4.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    4.20 : 5.81 = 2.91 : x
  2. Step 2: Convert to fraction form
    4.20/5.81 = 2.91/x
  3. Step 3: Cross multiply
    4.20x = 5.81 × 2.91
  4. Step 4: Simplify right side
    4.20x = 16.90
  5. Step 5: Solve for x
    x = 16.90/4.20
  6. Step 6: Final answer
    x = 4.02

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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.