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Finding the Fourth Proportional to 31.91, 47.80 and 18.35

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Solution

The fourth proportional to 31.91, 47.80 and 18.35 is: 27.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.91 : 47.80 = 18.35 : x
  2. Step 2: Convert to fraction form
    31.91/47.80 = 18.35/x
  3. Step 3: Cross multiply
    31.91x = 47.80 × 18.35
  4. Step 4: Simplify right side
    31.91x = 877.25
  5. Step 5: Solve for x
    x = 877.25/31.91
  6. Step 6: Final answer
    x = 27.49

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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.