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Finding the Fourth Proportional to 39.45, 54.36 and 31.71

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Solution

The fourth proportional to 39.45, 54.36 and 31.71 is: 43.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    39.45 : 54.36 = 31.71 : x
  2. Step 2: Convert to fraction form
    39.45/54.36 = 31.71/x
  3. Step 3: Cross multiply
    39.45x = 54.36 × 31.71
  4. Step 4: Simplify right side
    39.45x = 1,723.76
  5. Step 5: Solve for x
    x = 1,723.76/39.45
  6. Step 6: Final answer
    x = 43.69

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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.