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Finding the Fourth Proportional to 80.47, 120.70 and 19.60

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Solution

The fourth proportional to 80.47, 120.70 and 19.60 is: 29.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.47 : 120.70 = 19.60 : x
  2. Step 2: Convert to fraction form
    80.47/120.70 = 19.60/x
  3. Step 3: Cross multiply
    80.47x = 120.70 × 19.60
  4. Step 4: Simplify right side
    80.47x = 2,365.37
  5. Step 5: Solve for x
    x = 2,365.37/80.47
  6. Step 6: Final answer
    x = 29.40

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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.