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Finding the Fourth Proportional to 672.72, 1,008.79 and 261.78

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Solution

The fourth proportional to 672.72, 1,008.79 and 261.78 is: 392.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    672.72 : 1,008.79 = 261.78 : x
  2. Step 2: Convert to fraction form
    672.72/1,008.79 = 261.78/x
  3. Step 3: Cross multiply
    672.72x = 1,008.79 × 261.78
  4. Step 4: Simplify right side
    672.72x = 264,081.05
  5. Step 5: Solve for x
    x = 264,081.05/672.72
  6. Step 6: Final answer
    x = 392.56

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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.