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Finding the Fourth Proportional to 1,279.85, 1,918.19 and 663.20

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Solution

The fourth proportional to 1,279.85, 1,918.19 and 663.20 is: 993.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.85 : 1,918.19 = 663.20 : x
  2. Step 2: Convert to fraction form
    1,279.85/1,918.19 = 663.20/x
  3. Step 3: Cross multiply
    1,279.85x = 1,918.19 × 663.20
  4. Step 4: Simplify right side
    1,279.85x = 1,272,130.70
  5. Step 5: Solve for x
    x = 1,272,130.70/1,279.85
  6. Step 6: Final answer
    x = 993.97

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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.