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Finding the Fourth Proportional to 2,103.78, 3,156.30 and 642.90

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Solution

The fourth proportional to 2,103.78, 3,156.30 and 642.90 is: 964.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,103.78 : 3,156.30 = 642.90 : x
  2. Step 2: Convert to fraction form
    2,103.78/3,156.30 = 642.90/x
  3. Step 3: Cross multiply
    2,103.78x = 3,156.30 × 642.90
  4. Step 4: Simplify right side
    2,103.78x = 2,029,185.27
  5. Step 5: Solve for x
    x = 2,029,185.27/2,103.78
  6. Step 6: Final answer
    x = 964.54

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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.