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Finding the Fourth Proportional to 21.05, 28.97 and 18.47

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Solution

The fourth proportional to 21.05, 28.97 and 18.47 is: 25.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.05 : 28.97 = 18.47 : x
  2. Step 2: Convert to fraction form
    21.05/28.97 = 18.47/x
  3. Step 3: Cross multiply
    21.05x = 28.97 × 18.47
  4. Step 4: Simplify right side
    21.05x = 534.84
  5. Step 5: Solve for x
    x = 534.84/21.05
  6. Step 6: Final answer
    x = 25.41

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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.