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Finding the Fourth Proportional to 21.69, 29.90 and 18.61

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Solution

The fourth proportional to 21.69, 29.90 and 18.61 is: 25.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.69 : 29.90 = 18.61 : x
  2. Step 2: Convert to fraction form
    21.69/29.90 = 18.61/x
  3. Step 3: Cross multiply
    21.69x = 29.90 × 18.61
  4. Step 4: Simplify right side
    21.69x = 556.41
  5. Step 5: Solve for x
    x = 556.41/21.69
  6. Step 6: Final answer
    x = 25.65

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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.