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Finding the Fourth Proportional to 489.78, 675.64 and 396.63

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Solution

The fourth proportional to 489.78, 675.64 and 396.63 is: 547.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.78 : 675.64 = 396.63 : x
  2. Step 2: Convert to fraction form
    489.78/675.64 = 396.63/x
  3. Step 3: Cross multiply
    489.78x = 675.64 × 396.63
  4. Step 4: Simplify right side
    489.78x = 267,979.59
  5. Step 5: Solve for x
    x = 267,979.59/489.78
  6. Step 6: Final answer
    x = 547.14

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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.