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Finding the Fourth Proportional to 489.07, 674.61 and 390.79

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Solution

The fourth proportional to 489.07, 674.61 and 390.79 is: 539.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.07 : 674.61 = 390.79 : x
  2. Step 2: Convert to fraction form
    489.07/674.61 = 390.79/x
  3. Step 3: Cross multiply
    489.07x = 674.61 × 390.79
  4. Step 4: Simplify right side
    489.07x = 263,630.84
  5. Step 5: Solve for x
    x = 263,630.84/489.07
  6. Step 6: Final answer
    x = 539.05

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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.