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Finding the Fourth Proportional to 2.15, 3.21 and 1.81

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Solution

The fourth proportional to 2.15, 3.21 and 1.81 is: 2.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    2.15 : 3.21 = 1.81 : x
  2. Step 2: Convert to fraction form
    2.15/3.21 = 1.81/x
  3. Step 3: Cross multiply
    2.15x = 3.21 × 1.81
  4. Step 4: Simplify right side
    2.15x = 5.81
  5. Step 5: Solve for x
    x = 5.81/2.15
  6. Step 6: Final answer
    x = 2.70

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.