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Finding the Fourth Proportional to 20.69, 28.58 and 20.42

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Solution

The fourth proportional to 20.69, 28.58 and 20.42 is: 28.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.69 : 28.58 = 20.42 : x
  2. Step 2: Convert to fraction form
    20.69/28.58 = 20.42/x
  3. Step 3: Cross multiply
    20.69x = 28.58 × 20.42
  4. Step 4: Simplify right side
    20.69x = 583.36
  5. Step 5: Solve for x
    x = 583.36/20.69
  6. Step 6: Final answer
    x = 28.20

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1.5x scale

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.