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Finding the Fourth Proportional to 6.81, 10.21 and 2.80

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Solution

The fourth proportional to 6.81, 10.21 and 2.80 is: 4.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.81 : 10.21 = 2.80 : x
  2. Step 2: Convert to fraction form
    6.81/10.21 = 2.80/x
  3. Step 3: Cross multiply
    6.81x = 10.21 × 2.80
  4. Step 4: Simplify right side
    6.81x = 28.59
  5. Step 5: Solve for x
    x = 28.59/6.81
  6. Step 6: Final answer
    x = 4.20

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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.