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Finding the Fourth Proportional to 643.89, 965.98 and 278.70

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Solution

The fourth proportional to 643.89, 965.98 and 278.70 is: 418.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.89 : 965.98 = 278.70 : x
  2. Step 2: Convert to fraction form
    643.89/965.98 = 278.70/x
  3. Step 3: Cross multiply
    643.89x = 965.98 × 278.70
  4. Step 4: Simplify right side
    643.89x = 269,218.63
  5. Step 5: Solve for x
    x = 269,218.63/643.89
  6. Step 6: Final answer
    x = 418.11

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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.