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Finding the Fourth Proportional to 678.11, 1,016.66 and 287.80

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Solution

The fourth proportional to 678.11, 1,016.66 and 287.80 is: 431.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.11 : 1,016.66 = 287.80 : x
  2. Step 2: Convert to fraction form
    678.11/1,016.66 = 287.80/x
  3. Step 3: Cross multiply
    678.11x = 1,016.66 × 287.80
  4. Step 4: Simplify right side
    678.11x = 292,592.93
  5. Step 5: Solve for x
    x = 292,592.93/678.11
  6. Step 6: Final answer
    x = 431.48

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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.