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Finding the Fourth Proportional to 209.21, 313.85 and 87.48

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Solution

The fourth proportional to 209.21, 313.85 and 87.48 is: 131.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.21 : 313.85 = 87.48 : x
  2. Step 2: Convert to fraction form
    209.21/313.85 = 87.48/x
  3. Step 3: Cross multiply
    209.21x = 313.85 × 87.48
  4. Step 4: Simplify right side
    209.21x = 27,455.60
  5. Step 5: Solve for x
    x = 27,455.60/209.21
  6. Step 6: Final answer
    x = 131.23

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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.