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Finding the Fourth Proportional to 15.39, 21.11 and 15.17

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Solution

The fourth proportional to 15.39, 21.11 and 15.17 is: 20.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.39 : 21.11 = 15.17 : x
  2. Step 2: Convert to fraction form
    15.39/21.11 = 15.17/x
  3. Step 3: Cross multiply
    15.39x = 21.11 × 15.17
  4. Step 4: Simplify right side
    15.39x = 320.06
  5. Step 5: Solve for x
    x = 320.06/15.39
  6. Step 6: Final answer
    x = 20.80

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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.