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Finding the Fourth Proportional to 20.61, 30.72 and 19.77

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Solution

The fourth proportional to 20.61, 30.72 and 19.77 is: 29.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.61 : 30.72 = 19.77 : x
  2. Step 2: Convert to fraction form
    20.61/30.72 = 19.77/x
  3. Step 3: Cross multiply
    20.61x = 30.72 × 19.77
  4. Step 4: Simplify right side
    20.61x = 607.33
  5. Step 5: Solve for x
    x = 607.33/20.61
  6. Step 6: Final answer
    x = 29.47

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.