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Finding the Fourth Proportional to 678.12, 1,017.42 and 326.88

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Solution

The fourth proportional to 678.12, 1,017.42 and 326.88 is: 490.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.12 : 1,017.42 = 326.88 : x
  2. Step 2: Convert to fraction form
    678.12/1,017.42 = 326.88/x
  3. Step 3: Cross multiply
    678.12x = 1,017.42 × 326.88
  4. Step 4: Simplify right side
    678.12x = 332,574.25
  5. Step 5: Solve for x
    x = 332,574.25/678.12
  6. Step 6: Final answer
    x = 490.44

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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.