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Finding the Fourth Proportional to 672.28, 1,008.78 and 287.56

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Solution

The fourth proportional to 672.28, 1,008.78 and 287.56 is: 431.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    672.28 : 1,008.78 = 287.56 : x
  2. Step 2: Convert to fraction form
    672.28/1,008.78 = 287.56/x
  3. Step 3: Cross multiply
    672.28x = 1,008.78 × 287.56
  4. Step 4: Simplify right side
    672.28x = 290,084.78
  5. Step 5: Solve for x
    x = 290,084.78/672.28
  6. Step 6: Final answer
    x = 431.49

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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.