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Finding the Fourth Proportional to 1,278.25, 1,764.86 and 978.97

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Solution

The fourth proportional to 1,278.25, 1,764.86 and 978.97 is: 1,351.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.25 : 1,764.86 = 978.97 : x
  2. Step 2: Convert to fraction form
    1,278.25/1,764.86 = 978.97/x
  3. Step 3: Cross multiply
    1,278.25x = 1,764.86 × 978.97
  4. Step 4: Simplify right side
    1,278.25x = 1,727,738.37
  5. Step 5: Solve for x
    x = 1,727,738.37/1,278.25
  6. Step 6: Final answer
    x = 1,351.64

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.