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Finding the Fourth Proportional to 643.55, 964.36 and 278.13

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Solution

The fourth proportional to 643.55, 964.36 and 278.13 is: 416.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.55 : 964.36 = 278.13 : x
  2. Step 2: Convert to fraction form
    643.55/964.36 = 278.13/x
  3. Step 3: Cross multiply
    643.55x = 964.36 × 278.13
  4. Step 4: Simplify right side
    643.55x = 268,219.85
  5. Step 5: Solve for x
    x = 268,219.85/643.55
  6. Step 6: Final answer
    x = 416.78

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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.