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Finding the Fourth Proportional to 31.80, 47.70 and 19.84

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Solution

The fourth proportional to 31.80, 47.70 and 19.84 is: 29.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.80 : 47.70 = 19.84 : x
  2. Step 2: Convert to fraction form
    31.80/47.70 = 19.84/x
  3. Step 3: Cross multiply
    31.80x = 47.70 × 19.84
  4. Step 4: Simplify right side
    31.80x = 946.37
  5. Step 5: Solve for x
    x = 946.37/31.80
  6. Step 6: Final answer
    x = 29.76

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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.