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Finding the Fourth Proportional to 7.21, 10.81 and 3.20

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Solution

The fourth proportional to 7.21, 10.81 and 3.20 is: 4.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.21 : 10.81 = 3.20 : x
  2. Step 2: Convert to fraction form
    7.21/10.81 = 3.20/x
  3. Step 3: Cross multiply
    7.21x = 10.81 × 3.20
  4. Step 4: Simplify right side
    7.21x = 34.59
  5. Step 5: Solve for x
    x = 34.59/7.21
  6. Step 6: Final answer
    x = 4.80

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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.