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Finding the Fourth Proportional to 1,387.89, 2,081.87 and 657.54

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Solution

The fourth proportional to 1,387.89, 2,081.87 and 657.54 is: 986.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,387.89 : 2,081.87 = 657.54 : x
  2. Step 2: Convert to fraction form
    1,387.89/2,081.87 = 657.54/x
  3. Step 3: Cross multiply
    1,387.89x = 2,081.87 × 657.54
  4. Step 4: Simplify right side
    1,387.89x = 1,368,909.51
  5. Step 5: Solve for x
    x = 1,368,909.51/1,387.89
  6. Step 6: Final answer
    x = 986.32

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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.