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Finding the Fourth Proportional to 1,279.81, 1,919.89 and 458.31

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Solution

The fourth proportional to 1,279.81, 1,919.89 and 458.31 is: 687.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,279.81 : 1,919.89 = 458.31 : x
  2. Step 2: Convert to fraction form
    1,279.81/1,919.89 = 458.31/x
  3. Step 3: Cross multiply
    1,279.81x = 1,919.89 × 458.31
  4. Step 4: Simplify right side
    1,279.81x = 879,904.79
  5. Step 5: Solve for x
    x = 879,904.79/1,279.81
  6. Step 6: Final answer
    x = 687.53

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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.