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Finding the Fourth Proportional to 20.71, 28.58 and 13.45

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Solution

The fourth proportional to 20.71, 28.58 and 13.45 is: 18.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.71 : 28.58 = 13.45 : x
  2. Step 2: Convert to fraction form
    20.71/28.58 = 13.45/x
  3. Step 3: Cross multiply
    20.71x = 28.58 × 13.45
  4. Step 4: Simplify right side
    20.71x = 384.40
  5. Step 5: Solve for x
    x = 384.40/20.71
  6. Step 6: Final answer
    x = 18.56

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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.