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Finding the Fourth Proportional to 28.45, 39.18 and 19.71

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Solution

The fourth proportional to 28.45, 39.18 and 19.71 is: 27.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.45 : 39.18 = 19.71 : x
  2. Step 2: Convert to fraction form
    28.45/39.18 = 19.71/x
  3. Step 3: Cross multiply
    28.45x = 39.18 × 19.71
  4. Step 4: Simplify right side
    28.45x = 772.31
  5. Step 5: Solve for x
    x = 772.31/28.45
  6. Step 6: Final answer
    x = 27.15

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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.