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Finding the Fourth Proportional to 20.79, 28.71 and 13.53

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Solution

The fourth proportional to 20.79, 28.71 and 13.53 is: 18.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.79 : 28.71 = 13.53 : x
  2. Step 2: Convert to fraction form
    20.79/28.71 = 13.53/x
  3. Step 3: Cross multiply
    20.79x = 28.71 × 13.53
  4. Step 4: Simplify right side
    20.79x = 388.45
  5. Step 5: Solve for x
    x = 388.45/20.79
  6. Step 6: Final answer
    x = 18.68

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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.