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Finding the Fourth Proportional to 489.78, 675.90 and 279.95

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Solution

The fourth proportional to 489.78, 675.90 and 279.95 is: 386.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.78 : 675.90 = 279.95 : x
  2. Step 2: Convert to fraction form
    489.78/675.90 = 279.95/x
  3. Step 3: Cross multiply
    489.78x = 675.90 × 279.95
  4. Step 4: Simplify right side
    489.78x = 189,214.83
  5. Step 5: Solve for x
    x = 189,214.83/489.78
  6. Step 6: Final answer
    x = 386.33

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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.