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Finding the Fourth Proportional to 209.45, 313.99 and 87.64

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Solution

The fourth proportional to 209.45, 313.99 and 87.64 is: 131.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.45 : 313.99 = 87.64 : x
  2. Step 2: Convert to fraction form
    209.45/313.99 = 87.64/x
  3. Step 3: Cross multiply
    209.45x = 313.99 × 87.64
  4. Step 4: Simplify right side
    209.45x = 27,517.57
  5. Step 5: Solve for x
    x = 27,517.57/209.45
  6. Step 6: Final answer
    x = 131.38

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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.