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Finding the Fourth Proportional to 209.21, 313.43 and 87.17

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Solution

The fourth proportional to 209.21, 313.43 and 87.17 is: 130.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.21 : 313.43 = 87.17 : x
  2. Step 2: Convert to fraction form
    209.21/313.43 = 87.17/x
  3. Step 3: Cross multiply
    209.21x = 313.43 × 87.17
  4. Step 4: Simplify right side
    209.21x = 27,319.69
  5. Step 5: Solve for x
    x = 27,319.69/209.21
  6. Step 6: Final answer
    x = 130.59

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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.