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Finding the Fourth Proportional to 1,288.82, 1,780.89 and 1,028.90

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Solution

The fourth proportional to 1,288.82, 1,780.89 and 1,028.90 is: 1,421.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,288.82 : 1,780.89 = 1,028.90 : x
  2. Step 2: Convert to fraction form
    1,288.82/1,780.89 = 1,028.90/x
  3. Step 3: Cross multiply
    1,288.82x = 1,780.89 × 1,028.90
  4. Step 4: Simplify right side
    1,288.82x = 1,832,357.72
  5. Step 5: Solve for x
    x = 1,832,357.72/1,288.82
  6. Step 6: Final answer
    x = 1,421.73

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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.