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Finding the Fourth Proportional to 709.98, 980.30 and 489.40

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Solution

The fourth proportional to 709.98, 980.30 and 489.40 is: 675.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.98 : 980.30 = 489.40 : x
  2. Step 2: Convert to fraction form
    709.98/980.30 = 489.40/x
  3. Step 3: Cross multiply
    709.98x = 980.30 × 489.40
  4. Step 4: Simplify right side
    709.98x = 479,758.82
  5. Step 5: Solve for x
    x = 479,758.82/709.98
  6. Step 6: Final answer
    x = 675.74

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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.