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Finding the Fourth Proportional to 28.30, 39.08 and 21.76

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Solution

The fourth proportional to 28.30, 39.08 and 21.76 is: 30.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.30 : 39.08 = 21.76 : x
  2. Step 2: Convert to fraction form
    28.30/39.08 = 21.76/x
  3. Step 3: Cross multiply
    28.30x = 39.08 × 21.76
  4. Step 4: Simplify right side
    28.30x = 850.33
  5. Step 5: Solve for x
    x = 850.33/28.30
  6. Step 6: Final answer
    x = 30.04

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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.