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Finding the Fourth Proportional to 1,379.40, 2,067.28 and 647.98

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Solution

The fourth proportional to 1,379.40, 2,067.28 and 647.98 is: 971.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,379.40 : 2,067.28 = 647.98 : x
  2. Step 2: Convert to fraction form
    1,379.40/2,067.28 = 647.98/x
  3. Step 3: Cross multiply
    1,379.40x = 2,067.28 × 647.98
  4. Step 4: Simplify right side
    1,379.40x = 1,339,556.09
  5. Step 5: Solve for x
    x = 1,339,556.09/1,379.40
  6. Step 6: Final answer
    x = 971.12

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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.