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Finding the Fourth Proportional to 643.94, 965.34 and 278.78

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Solution

The fourth proportional to 643.94, 965.34 and 278.78 is: 417.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.94 : 965.34 = 278.78 : x
  2. Step 2: Convert to fraction form
    643.94/965.34 = 278.78/x
  3. Step 3: Cross multiply
    643.94x = 965.34 × 278.78
  4. Step 4: Simplify right side
    643.94x = 269,117.49
  5. Step 5: Solve for x
    x = 269,117.49/643.94
  6. Step 6: Final answer
    x = 417.92

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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.