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Finding the Fourth Proportional to 1,687.87, 2,531.30 and 647.79

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Solution

The fourth proportional to 1,687.87, 2,531.30 and 647.79 is: 971.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,687.87 : 2,531.30 = 647.79 : x
  2. Step 2: Convert to fraction form
    1,687.87/2,531.30 = 647.79/x
  3. Step 3: Cross multiply
    1,687.87x = 2,531.30 × 647.79
  4. Step 4: Simplify right side
    1,687.87x = 1,639,750.83
  5. Step 5: Solve for x
    x = 1,639,750.83/1,687.87
  6. Step 6: Final answer
    x = 971.49

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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.