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Finding the Fourth Proportional to 489.12, 674.90 and 279.20

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Solution

The fourth proportional to 489.12, 674.90 and 279.20 is: 385.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.12 : 674.90 = 279.20 : x
  2. Step 2: Convert to fraction form
    489.12/674.90 = 279.20/x
  3. Step 3: Cross multiply
    489.12x = 674.90 × 279.20
  4. Step 4: Simplify right side
    489.12x = 188,432.08
  5. Step 5: Solve for x
    x = 188,432.08/489.12
  6. Step 6: Final answer
    x = 385.25

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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.