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Finding the Fourth Proportional to 15.72, 21.67 and 12.09

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Solution

The fourth proportional to 15.72, 21.67 and 12.09 is: 16.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.72 : 21.67 = 12.09 : x
  2. Step 2: Convert to fraction form
    15.72/21.67 = 12.09/x
  3. Step 3: Cross multiply
    15.72x = 21.67 × 12.09
  4. Step 4: Simplify right side
    15.72x = 261.99
  5. Step 5: Solve for x
    x = 261.99/15.72
  6. Step 6: Final answer
    x = 16.67

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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.