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Finding the Fourth Proportional to 1,278.39, 1,763.87 and 858

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Solution

The fourth proportional to 1,278.39, 1,763.87 and 858 is: 1,183.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.39 : 1,763.87 = 858 : x
  2. Step 2: Convert to fraction form
    1,278.39/1,763.87 = 858/x
  3. Step 3: Cross multiply
    1,278.39x = 1,763.87 × 858
  4. Step 4: Simplify right side
    1,278.39x = 1,513,396.17
  5. Step 5: Solve for x
    x = 1,513,396.17/1,278.39
  6. Step 6: Final answer
    x = 1,183.83

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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.