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Finding the Fourth Proportional to 21.27, 31.91 and 18.76

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Solution

The fourth proportional to 21.27, 31.91 and 18.76 is: 28.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.27 : 31.91 = 18.76 : x
  2. Step 2: Convert to fraction form
    21.27/31.91 = 18.76/x
  3. Step 3: Cross multiply
    21.27x = 31.91 × 18.76
  4. Step 4: Simplify right side
    21.27x = 598.46
  5. Step 5: Solve for x
    x = 598.46/21.27
  6. Step 6: Final answer
    x = 28.14

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.