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Finding the Fourth Proportional to 486.20, 670.90 and 289.69

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Solution

The fourth proportional to 486.20, 670.90 and 289.69 is: 399.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.20 : 670.90 = 289.69 : x
  2. Step 2: Convert to fraction form
    486.20/670.90 = 289.69/x
  3. Step 3: Cross multiply
    486.20x = 670.90 × 289.69
  4. Step 4: Simplify right side
    486.20x = 194,353.02
  5. Step 5: Solve for x
    x = 194,353.02/486.20
  6. Step 6: Final answer
    x = 399.74

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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.