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Finding the Fourth Proportional to 1,387.56, 2,081.40 and 618

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Solution

The fourth proportional to 1,387.56, 2,081.40 and 618 is: 927.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.56 : 2,081.40 = 618 : x
  2. Step 2: Convert to fraction form
    1,387.56/2,081.40 = 618/x
  3. Step 3: Cross multiply
    1,387.56x = 2,081.40 × 618
  4. Step 4: Simplify right side
    1,387.56x = 1,286,305.20
  5. Step 5: Solve for x
    x = 1,286,305.20/1,387.56
  6. Step 6: Final answer
    x = 927.03

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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.