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Finding the Fourth Proportional to 391.89, 588.42 and 218.90

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Solution

The fourth proportional to 391.89, 588.42 and 218.90 is: 328.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.89 : 588.42 = 218.90 : x
  2. Step 2: Convert to fraction form
    391.89/588.42 = 218.90/x
  3. Step 3: Cross multiply
    391.89x = 588.42 × 218.90
  4. Step 4: Simplify right side
    391.89x = 128,801.10
  5. Step 5: Solve for x
    x = 128,801.10/391.89
  6. Step 6: Final answer
    x = 328.67

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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.