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Finding the Fourth Proportional to 2.81, 4.21 and 1.80

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Solution

The fourth proportional to 2.81, 4.21 and 1.80 is: 2.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    2.81 : 4.21 = 1.80 : x
  2. Step 2: Convert to fraction form
    2.81/4.21 = 1.80/x
  3. Step 3: Cross multiply
    2.81x = 4.21 × 1.80
  4. Step 4: Simplify right side
    2.81x = 7.58
  5. Step 5: Solve for x
    x = 7.58/2.81
  6. Step 6: Final answer
    x = 2.70

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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.