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Finding the Fourth Proportional to 31.22, 46.80 and 19.20

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Solution

The fourth proportional to 31.22, 46.80 and 19.20 is: 28.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.22 : 46.80 = 19.20 : x
  2. Step 2: Convert to fraction form
    31.22/46.80 = 19.20/x
  3. Step 3: Cross multiply
    31.22x = 46.80 × 19.20
  4. Step 4: Simplify right side
    31.22x = 898.56
  5. Step 5: Solve for x
    x = 898.56/31.22
  6. Step 6: Final answer
    x = 28.79

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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.