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Finding the Fourth Proportional to 21.64, 29.86 and 12.42

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Solution

The fourth proportional to 21.64, 29.86 and 12.42 is: 17.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.64 : 29.86 = 12.42 : x
  2. Step 2: Convert to fraction form
    21.64/29.86 = 12.42/x
  3. Step 3: Cross multiply
    21.64x = 29.86 × 12.42
  4. Step 4: Simplify right side
    21.64x = 370.86
  5. Step 5: Solve for x
    x = 370.86/21.64
  6. Step 6: Final answer
    x = 17.14

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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.