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Finding the Fourth Proportional to 4.80, 7.20 and 3.91

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Solution

The fourth proportional to 4.80, 7.20 and 3.91 is: 5.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    4.80 : 7.20 = 3.91 : x
  2. Step 2: Convert to fraction form
    4.80/7.20 = 3.91/x
  3. Step 3: Cross multiply
    4.80x = 7.20 × 3.91
  4. Step 4: Simplify right side
    4.80x = 28.10
  5. Step 5: Solve for x
    x = 28.10/4.80
  6. Step 6: Final answer
    x = 5.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.