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Finding the Fourth Proportional to 1,660.92, 2,491.35 and 428.31

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Solution

The fourth proportional to 1,660.92, 2,491.35 and 428.31 is: 642.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,660.92 : 2,491.35 = 428.31 : x
  2. Step 2: Convert to fraction form
    1,660.92/2,491.35 = 428.31/x
  3. Step 3: Cross multiply
    1,660.92x = 2,491.35 × 428.31
  4. Step 4: Simplify right side
    1,660.92x = 1,067,070.12
  5. Step 5: Solve for x
    x = 1,067,070.12/1,660.92
  6. Step 6: Final answer
    x = 642.46

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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.