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Finding the Fourth Proportional to 391.84, 587.79 and 209.18

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Solution

The fourth proportional to 391.84, 587.79 and 209.18 is: 313.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.84 : 587.79 = 209.18 : x
  2. Step 2: Convert to fraction form
    391.84/587.79 = 209.18/x
  3. Step 3: Cross multiply
    391.84x = 587.79 × 209.18
  4. Step 4: Simplify right side
    391.84x = 122,955.38
  5. Step 5: Solve for x
    x = 122,955.38/391.84
  6. Step 6: Final answer
    x = 313.79

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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.