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Finding the Fourth Proportional to 47.20, 70.80 and 20.17

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Solution

The fourth proportional to 47.20, 70.80 and 20.17 is: 30.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.20 : 70.80 = 20.17 : x
  2. Step 2: Convert to fraction form
    47.20/70.80 = 20.17/x
  3. Step 3: Cross multiply
    47.20x = 70.80 × 20.17
  4. Step 4: Simplify right side
    47.20x = 1,427.58
  5. Step 5: Solve for x
    x = 1,427.58/47.20
  6. Step 6: Final answer
    x = 30.25

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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.