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Finding the Fourth Proportional to 1,387.81, 2,079.91 and 1,240.69

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Solution

The fourth proportional to 1,387.81, 2,079.91 and 1,240.69 is: 1,859.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.81 : 2,079.91 = 1,240.69 : x
  2. Step 2: Convert to fraction form
    1,387.81/2,079.91 = 1,240.69/x
  3. Step 3: Cross multiply
    1,387.81x = 2,079.91 × 1,240.69
  4. Step 4: Simplify right side
    1,387.81x = 2,580,523.54
  5. Step 5: Solve for x
    x = 2,580,523.54/1,387.81
  6. Step 6: Final answer
    x = 1,859.42

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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.