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Finding the Fourth Proportional to 5.47, 8.21 and 1.91

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Solution

The fourth proportional to 5.47, 8.21 and 1.91 is: 2.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    5.47 : 8.21 = 1.91 : x
  2. Step 2: Convert to fraction form
    5.47/8.21 = 1.91/x
  3. Step 3: Cross multiply
    5.47x = 8.21 × 1.91
  4. Step 4: Simplify right side
    5.47x = 15.63
  5. Step 5: Solve for x
    x = 15.63/5.47
  6. Step 6: Final answer
    x = 2.86

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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.