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Finding the Fourth Proportional to 15.78, 21.77 and 12.09

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Solution

The fourth proportional to 15.78, 21.77 and 12.09 is: 16.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.78 : 21.77 = 12.09 : x
  2. Step 2: Convert to fraction form
    15.78/21.77 = 12.09/x
  3. Step 3: Cross multiply
    15.78x = 21.77 × 12.09
  4. Step 4: Simplify right side
    15.78x = 263.14
  5. Step 5: Solve for x
    x = 263.14/15.78
  6. Step 6: Final answer
    x = 16.68

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.