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Finding the Fourth Proportional to 28.84, 39.81 and 15.91

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Solution

The fourth proportional to 28.84, 39.81 and 15.91 is: 21.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.84 : 39.81 = 15.91 : x
  2. Step 2: Convert to fraction form
    28.84/39.81 = 15.91/x
  3. Step 3: Cross multiply
    28.84x = 39.81 × 15.91
  4. Step 4: Simplify right side
    28.84x = 633.15
  5. Step 5: Solve for x
    x = 633.15/28.84
  6. Step 6: Final answer
    x = 21.95

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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.