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Finding the Fourth Proportional to 1,378.42, 2,067.98 and 647.15

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Solution

The fourth proportional to 1,378.42, 2,067.98 and 647.15 is: 970.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,378.42 : 2,067.98 = 647.15 : x
  2. Step 2: Convert to fraction form
    1,378.42/2,067.98 = 647.15/x
  3. Step 3: Cross multiply
    1,378.42x = 2,067.98 × 647.15
  4. Step 4: Simplify right side
    1,378.42x = 1,338,279.68
  5. Step 5: Solve for x
    x = 1,338,279.68/1,378.42
  6. Step 6: Final answer
    x = 970.88

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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.