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Finding the Fourth Proportional to 1,279.11, 1,919.70 and 663

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Solution

The fourth proportional to 1,279.11, 1,919.70 and 663 is: 995.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.11 : 1,919.70 = 663 : x
  2. Step 2: Convert to fraction form
    1,279.11/1,919.70 = 663/x
  3. Step 3: Cross multiply
    1,279.11x = 1,919.70 × 663
  4. Step 4: Simplify right side
    1,279.11x = 1,272,761.10
  5. Step 5: Solve for x
    x = 1,272,761.10/1,279.11
  6. Step 6: Final answer
    x = 995.04

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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.