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Finding the Fourth Proportional to 21.72, 29.60 and 21.64

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Solution

The fourth proportional to 21.72, 29.60 and 21.64 is: 29.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.72 : 29.60 = 21.64 : x
  2. Step 2: Convert to fraction form
    21.72/29.60 = 21.64/x
  3. Step 3: Cross multiply
    21.72x = 29.60 × 21.64
  4. Step 4: Simplify right side
    21.72x = 640.54
  5. Step 5: Solve for x
    x = 640.54/21.72
  6. Step 6: Final answer
    x = 29.49

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.