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Finding the Fourth Proportional to 1,278.92, 1,918.62 and 758.72

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Solution

The fourth proportional to 1,278.92, 1,918.62 and 758.72 is: 1,138.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,278.92 : 1,918.62 = 758.72 : x
  2. Step 2: Convert to fraction form
    1,278.92/1,918.62 = 758.72/x
  3. Step 3: Cross multiply
    1,278.92x = 1,918.62 × 758.72
  4. Step 4: Simplify right side
    1,278.92x = 1,455,695.37
  5. Step 5: Solve for x
    x = 1,455,695.37/1,278.92
  6. Step 6: Final answer
    x = 1,138.22

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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.