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Finding the Fourth Proportional to 209.71, 314.57 and 87.85

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Solution

The fourth proportional to 209.71, 314.57 and 87.85 is: 131.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.71 : 314.57 = 87.85 : x
  2. Step 2: Convert to fraction form
    209.71/314.57 = 87.85/x
  3. Step 3: Cross multiply
    209.71x = 314.57 × 87.85
  4. Step 4: Simplify right side
    209.71x = 27,634.41
  5. Step 5: Solve for x
    x = 27,634.41/209.71
  6. Step 6: Final answer
    x = 131.78

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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.