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Finding the Fourth Proportional to 209.64, 314.45 and 87.86

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Solution

The fourth proportional to 209.64, 314.45 and 87.86 is: 131.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.64 : 314.45 = 87.86 : x
  2. Step 2: Convert to fraction form
    209.64/314.45 = 87.86/x
  3. Step 3: Cross multiply
    209.64x = 314.45 × 87.86
  4. Step 4: Simplify right side
    209.64x = 27,627.58
  5. Step 5: Solve for x
    x = 27,627.58/209.64
  6. Step 6: Final answer
    x = 131.79

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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.