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Finding the Fourth Proportional to 15.72, 21.64 and 12.96

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Solution

The fourth proportional to 15.72, 21.64 and 12.96 is: 17.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    15.72 : 21.64 = 12.96 : x
  2. Step 2: Convert to fraction form
    15.72/21.64 = 12.96/x
  3. Step 3: Cross multiply
    15.72x = 21.64 × 12.96
  4. Step 4: Simplify right side
    15.72x = 280.45
  5. Step 5: Solve for x
    x = 280.45/15.72
  6. Step 6: Final answer
    x = 17.84

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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.