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Finding the Fourth Proportional to 31.20, 46.56 and 28.71

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Solution

The fourth proportional to 31.20, 46.56 and 28.71 is: 42.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.20 : 46.56 = 28.71 : x
  2. Step 2: Convert to fraction form
    31.20/46.56 = 28.71/x
  3. Step 3: Cross multiply
    31.20x = 46.56 × 28.71
  4. Step 4: Simplify right side
    31.20x = 1,336.74
  5. Step 5: Solve for x
    x = 1,336.74/31.20
  6. Step 6: Final answer
    x = 42.84

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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.