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Finding the Fourth Proportional to 20.56, 28.36 and 15.70

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Solution

The fourth proportional to 20.56, 28.36 and 15.70 is: 21.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.56 : 28.36 = 15.70 : x
  2. Step 2: Convert to fraction form
    20.56/28.36 = 15.70/x
  3. Step 3: Cross multiply
    20.56x = 28.36 × 15.70
  4. Step 4: Simplify right side
    20.56x = 445.25
  5. Step 5: Solve for x
    x = 445.25/20.56
  6. Step 6: Final answer
    x = 21.66

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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.