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Finding the Fourth Proportional to 15.21, 20.91 and 14.22

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Solution

The fourth proportional to 15.21, 20.91 and 14.22 is: 19.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.21 : 20.91 = 14.22 : x
  2. Step 2: Convert to fraction form
    15.21/20.91 = 14.22/x
  3. Step 3: Cross multiply
    15.21x = 20.91 × 14.22
  4. Step 4: Simplify right side
    15.21x = 297.34
  5. Step 5: Solve for x
    x = 297.34/15.21
  6. Step 6: Final answer
    x = 19.55

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.