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Finding the Fourth Proportional to 68.75, 103.20 and 28.20

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Solution

The fourth proportional to 68.75, 103.20 and 28.20 is: 42.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.75 : 103.20 = 28.20 : x
  2. Step 2: Convert to fraction form
    68.75/103.20 = 28.20/x
  3. Step 3: Cross multiply
    68.75x = 103.20 × 28.20
  4. Step 4: Simplify right side
    68.75x = 2,910.24
  5. Step 5: Solve for x
    x = 2,910.24/68.75
  6. Step 6: Final answer
    x = 42.33

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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.