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Finding the Fourth Proportional to 209.71, 314.46 and 77.88

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Solution

The fourth proportional to 209.71, 314.46 and 77.88 is: 116.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.71 : 314.46 = 77.88 : x
  2. Step 2: Convert to fraction form
    209.71/314.46 = 77.88/x
  3. Step 3: Cross multiply
    209.71x = 314.46 × 77.88
  4. Step 4: Simplify right side
    209.71x = 24,490.14
  5. Step 5: Solve for x
    x = 24,490.14/209.71
  6. Step 6: Final answer
    x = 116.78

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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.