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Finding the Fourth Proportional to 643.80, 966.12 and 278.76

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Solution

The fourth proportional to 643.80, 966.12 and 278.76 is: 418.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.80 : 966.12 = 278.76 : x
  2. Step 2: Convert to fraction form
    643.80/966.12 = 278.76/x
  3. Step 3: Cross multiply
    643.80x = 966.12 × 278.76
  4. Step 4: Simplify right side
    643.80x = 269,315.61
  5. Step 5: Solve for x
    x = 269,315.61/643.80
  6. Step 6: Final answer
    x = 418.32

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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.