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Finding the Fourth Proportional to 30.87, 42.57 and 28.82

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Solution

The fourth proportional to 30.87, 42.57 and 28.82 is: 39.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    30.87 : 42.57 = 28.82 : x
  2. Step 2: Convert to fraction form
    30.87/42.57 = 28.82/x
  3. Step 3: Cross multiply
    30.87x = 42.57 × 28.82
  4. Step 4: Simplify right side
    30.87x = 1,226.65
  5. Step 5: Solve for x
    x = 1,226.65/30.87
  6. Step 6: Final answer
    x = 39.74

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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.