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Finding the Fourth Proportional to 31.76, 47.64 and 28.80

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Solution

The fourth proportional to 31.76, 47.64 and 28.80 is: 43.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.76 : 47.64 = 28.80 : x
  2. Step 2: Convert to fraction form
    31.76/47.64 = 28.80/x
  3. Step 3: Cross multiply
    31.76x = 47.64 × 28.80
  4. Step 4: Simplify right side
    31.76x = 1,372.03
  5. Step 5: Solve for x
    x = 1,372.03/31.76
  6. Step 6: Final answer
    x = 43.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.