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Finding the Fourth Proportional to 2,178.40, 3,267.84 and 639.40

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Solution

The fourth proportional to 2,178.40, 3,267.84 and 639.40 is: 959.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,178.40 : 3,267.84 = 639.40 : x
  2. Step 2: Convert to fraction form
    2,178.40/3,267.84 = 639.40/x
  3. Step 3: Cross multiply
    2,178.40x = 3,267.84 × 639.40
  4. Step 4: Simplify right side
    2,178.40x = 2,089,456.90
  5. Step 5: Solve for x
    x = 2,089,456.90/2,178.40
  6. Step 6: Final answer
    x = 959.17

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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.