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Finding the Fourth Proportional to 709.75, 979.89 and 485.95

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Solution

The fourth proportional to 709.75, 979.89 and 485.95 is: 670.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    709.75 : 979.89 = 485.95 : x
  2. Step 2: Convert to fraction form
    709.75/979.89 = 485.95/x
  3. Step 3: Cross multiply
    709.75x = 979.89 × 485.95
  4. Step 4: Simplify right side
    709.75x = 476,177.55
  5. Step 5: Solve for x
    x = 476,177.55/709.75
  6. Step 6: Final answer
    x = 670.91

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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.