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Finding the Fourth Proportional to 30.75, 42.38 and 28.58

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Solution

The fourth proportional to 30.75, 42.38 and 28.58 is: 39.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.75 : 42.38 = 28.58 : x
  2. Step 2: Convert to fraction form
    30.75/42.38 = 28.58/x
  3. Step 3: Cross multiply
    30.75x = 42.38 × 28.58
  4. Step 4: Simplify right side
    30.75x = 1,211.22
  5. Step 5: Solve for x
    x = 1,211.22/30.75
  6. Step 6: Final answer
    x = 39.39

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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.