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Finding the Fourth Proportional to 31.49, 47.21 and 28.28

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Solution

The fourth proportional to 31.49, 47.21 and 28.28 is: 42.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.49 : 47.21 = 28.28 : x
  2. Step 2: Convert to fraction form
    31.49/47.21 = 28.28/x
  3. Step 3: Cross multiply
    31.49x = 47.21 × 28.28
  4. Step 4: Simplify right side
    31.49x = 1,335.10
  5. Step 5: Solve for x
    x = 1,335.10/31.49
  6. Step 6: Final answer
    x = 42.40

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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.