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Finding the Fourth Proportional to 2,181, 3,271.50 and 642

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Solution

The fourth proportional to 2,181, 3,271.50 and 642 is: 963

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,181 : 3,271.50 = 642 : x
  2. Step 2: Convert to fraction form
    2,181/3,271.50 = 642/x
  3. Step 3: Cross multiply
    2,181x = 3,271.50 × 642
  4. Step 4: Simplify right side
    2,181x = 2,100,303
  5. Step 5: Solve for x
    x = 2,100,303/2,181
  6. Step 6: Final answer
    x = 963

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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.