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Finding the Fourth Proportional to 489.78, 676.35 and 315.54

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Solution

The fourth proportional to 489.78, 676.35 and 315.54 is: 435.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.78 : 676.35 = 315.54 : x
  2. Step 2: Convert to fraction form
    489.78/676.35 = 315.54/x
  3. Step 3: Cross multiply
    489.78x = 676.35 × 315.54
  4. Step 4: Simplify right side
    489.78x = 213,415.48
  5. Step 5: Solve for x
    x = 213,415.48/489.78
  6. Step 6: Final answer
    x = 435.74

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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.