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Finding the Fourth Proportional to 28.04, 38.72 and 20.80

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Solution

The fourth proportional to 28.04, 38.72 and 20.80 is: 28.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.04 : 38.72 = 20.80 : x
  2. Step 2: Convert to fraction form
    28.04/38.72 = 20.80/x
  3. Step 3: Cross multiply
    28.04x = 38.72 × 20.80
  4. Step 4: Simplify right side
    28.04x = 805.38
  5. Step 5: Solve for x
    x = 805.38/28.04
  6. Step 6: Final answer
    x = 28.72

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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.