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Finding the Fourth Proportional to 21.27, 31.76 and 19.36

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Solution

The fourth proportional to 21.27, 31.76 and 19.36 is: 28.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.27 : 31.76 = 19.36 : x
  2. Step 2: Convert to fraction form
    21.27/31.76 = 19.36/x
  3. Step 3: Cross multiply
    21.27x = 31.76 × 19.36
  4. Step 4: Simplify right side
    21.27x = 614.87
  5. Step 5: Solve for x
    x = 614.87/21.27
  6. Step 6: Final answer
    x = 28.91

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.