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Finding the Fourth Proportional to 1,986.27, 2,979.54 and 687.84

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Solution

The fourth proportional to 1,986.27, 2,979.54 and 687.84 is: 1,031.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,986.27 : 2,979.54 = 687.84 : x
  2. Step 2: Convert to fraction form
    1,986.27/2,979.54 = 687.84/x
  3. Step 3: Cross multiply
    1,986.27x = 2,979.54 × 687.84
  4. Step 4: Simplify right side
    1,986.27x = 2,049,446.79
  5. Step 5: Solve for x
    x = 2,049,446.79/1,986.27
  6. Step 6: Final answer
    x = 1,031.81

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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.