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Finding the Fourth Proportional to 311.68, 428.97 and 289.32

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Solution

The fourth proportional to 311.68, 428.97 and 289.32 is: 398.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.68 : 428.97 = 289.32 : x
  2. Step 2: Convert to fraction form
    311.68/428.97 = 289.32/x
  3. Step 3: Cross multiply
    311.68x = 428.97 × 289.32
  4. Step 4: Simplify right side
    311.68x = 124,109.60
  5. Step 5: Solve for x
    x = 124,109.60/311.68
  6. Step 6: Final answer
    x = 398.20

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.