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Finding the Fourth Proportional to 979.80, 1,469.70 and 707.80

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Solution

The fourth proportional to 979.80, 1,469.70 and 707.80 is: 1,061.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    979.80 : 1,469.70 = 707.80 : x
  2. Step 2: Convert to fraction form
    979.80/1,469.70 = 707.80/x
  3. Step 3: Cross multiply
    979.80x = 1,469.70 × 707.80
  4. Step 4: Simplify right side
    979.80x = 1,040,253.66
  5. Step 5: Solve for x
    x = 1,040,253.66/979.80
  6. Step 6: Final answer
    x = 1,061.70

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.