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Finding the Fourth Proportional to 643.90, 966.06 and 278.80

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Solution

The fourth proportional to 643.90, 966.06 and 278.80 is: 418.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.90 : 966.06 = 278.80 : x
  2. Step 2: Convert to fraction form
    643.90/966.06 = 278.80/x
  3. Step 3: Cross multiply
    643.90x = 966.06 × 278.80
  4. Step 4: Simplify right side
    643.90x = 269,337.53
  5. Step 5: Solve for x
    x = 269,337.53/643.90
  6. Step 6: Final answer
    x = 418.29

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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.