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Finding the Fourth Proportional to 30.83, 42.54 and 20.47

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Solution

The fourth proportional to 30.83, 42.54 and 20.47 is: 28.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.83 : 42.54 = 20.47 : x
  2. Step 2: Convert to fraction form
    30.83/42.54 = 20.47/x
  3. Step 3: Cross multiply
    30.83x = 42.54 × 20.47
  4. Step 4: Simplify right side
    30.83x = 870.79
  5. Step 5: Solve for x
    x = 870.79/30.83
  6. Step 6: Final answer
    x = 28.25

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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.