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Finding the Fourth Proportional to 30.69, 42.33 and 20.31

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Solution

The fourth proportional to 30.69, 42.33 and 20.31 is: 28.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.69 : 42.33 = 20.31 : x
  2. Step 2: Convert to fraction form
    30.69/42.33 = 20.31/x
  3. Step 3: Cross multiply
    30.69x = 42.33 × 20.31
  4. Step 4: Simplify right side
    30.69x = 859.72
  5. Step 5: Solve for x
    x = 859.72/30.69
  6. Step 6: Final answer
    x = 28.01

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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.