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Finding the Fourth Proportional to 208.97, 313.21 and 87.20

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Solution

The fourth proportional to 208.97, 313.21 and 87.20 is: 130.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.97 : 313.21 = 87.20 : x
  2. Step 2: Convert to fraction form
    208.97/313.21 = 87.20/x
  3. Step 3: Cross multiply
    208.97x = 313.21 × 87.20
  4. Step 4: Simplify right side
    208.97x = 27,311.91
  5. Step 5: Solve for x
    x = 27,311.91/208.97
  6. Step 6: Final answer
    x = 130.70

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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.