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Finding the Fourth Proportional to 20.45, 30.72 and 19.30

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Solution

The fourth proportional to 20.45, 30.72 and 19.30 is: 28.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.45 : 30.72 = 19.30 : x
  2. Step 2: Convert to fraction form
    20.45/30.72 = 19.30/x
  3. Step 3: Cross multiply
    20.45x = 30.72 × 19.30
  4. Step 4: Simplify right side
    20.45x = 592.81
  5. Step 5: Solve for x
    x = 592.81/20.45
  6. Step 6: Final answer
    x = 28.98

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.